This post is one in a series in which more than 60 newsletter advisors share their Top Stock Picks for 2011. This special report is courtesy of TheStockAdvisors.com.

"Last year for my favorite stock pick, I recommended IMAX which more than doubled; this year I would like to recommend Siga Technologies (SIGA), which I believe offers the same kind of upside potential for 2011," says Dennis Slothower. Dennis's Top Pick in last year's report rose 99%.

The editor of Stealth Stocks explains, "Siga is a bio-defense company. In 2004, the U.S. started an initiative called Project BioShield, which gave the government the right to purchase and stockpile vaccines and drugs to fight anthrax, smallpox and other potential agents of bio-terror.

"Aerospace & defense contractor General Dynamics (GD) is a buy based on our value criteria," says J. Royden Ward.

The editor of Cabot Benjamin Graham Value Letter explains, "In our view, the shares are undervalued at 9.4 times forward 12-month EPS. Dividends have been paid since 1979 and currently provide a solid yield of 2.5%

"The company has an impressive record of increasing sales, earnings and dividends during the past 20 years which will continue unabated during the foreseeable future.

"It's been tough going for Lockheed Martin (LMT) in 2009-10, as well as for defense stocks overall," notes Stephen Leeb.

The editor of Leeb's Income Performance Letter explains, "Investors are concerned about the impact cutbacks in defense spending will have on profits. Still, the company arguably is the best positioned of the major defense contractors to weather a smaller defense budget.

"The company is bracing for leaner times and has taken cost-savings measures, such as offering early retirement incentives to executives. And its share price appears to have more than discounted any cuts that may come down the pike.

"The government is funneling cash into a new breed of defense companies that specialize in nonconventional warfare and intelligence gathering. Global Defense Technology (GTEC) is one such company," says growth stock specialist Karim Rahemtulla.

The contributing editor to White Cap Research Group explains, "The company was met with little fanfare when it went public in December 2009. But with earnings in hypergrowth mode, and sales ready to leap beyond its $140 million market cap, this company won't remain Wall Street's best-kept secret much longer.

"One defense-related investment that looks promising is the latest generation of unmanned aircraft," says Jim Powell.

The editor of Global Changes & Opportunities Report says, "The new 'drones' as they are usually called, are extremely sophisticated. Most of them, such as the updated Predator and its successor the Reaper, are operated remotely from half way around the world.

"Many other drones are fully automated. They fly to predetermined points using GPS coordinate, where they take photographs, listen to electronic communications, make maps, and do other surveillance work. Some of the automated drones can remain aloft for a long as 36 hours.

"Since the global financial meltdown and ensuing recession, there's been a lot of prognosticating about defense spending; most Wall Street analysts expected the Obama administration to use the economic crisis as a pretense to rein in the enormous defense budget," says Gregg Early, editor of Personal Finance.

"Nevertheless, in my view, if you buy into the best names now, there's plenty of upside left. With over a quarter of million troops stationed in active war zones, the administration is obligated to ensure that they're safe and effective. And combat zones are the ideal testing ground for new equipment.

"Boeing (BA) is on the short list of great American companies; Boeing's heritage as the premier U.S.-based airplane manufacturer is impressive," says Brandon Clay.

The editor of Invest with an Edge explains, "While the company isn't a monopoly on this front, it really only has one legitimate competitor: Airbus. With the global economy improving, at least for now, the airline business is looking up. That's good news for Boeing.

This post is part of a special report, Top Picks for 2010, the 27th annual survey in which TheStockAdvisors.com asks the nation's leading advisors for their single favorite stock for the new year. See all 80 stocks listed here.

Technology expert Gregg Early looks to AeroVironment (AVAV) as his top pick for the coming year.

The editor of The New Tech Investor -- and the soon-to-be-launched Portfolio 2020 -- he explains, "Although the firm's military aerospace business should be strong, it is the firm's new 'clean technology' and energy efficiency projects that should be the real growth kicker."

"For a pure play in automated and remotely controlled vehicles, consider iRobot (NASDAQ: IRBT)," says Jim Powell. Here's the latest from his Global Changes & Opportunities Report.

"The company is best known for its Roomba vacuum cleaners that wander around the house bumping into everything and setting off security alarms.

"A similar product cleans the surface of swimming pools. iRobot also makes automated mail and product delivery carts for businesses.

"Investors considering high-yield stocks should consider financial strength; in our quantitative model, Quadrix, we assess profit margins, interest coverage, and debt levels," says Richard Moroney.

In Dow Theory Forecasts, a newsletter that has been published for over 5 decades -- he looks at two stocks that score high in this area: drug manufacturer, AstraZeneca (NYSE: AZN) and defense industry player, General Dynamics (NYSE: GD). Here, the advisor reviews the two companies.

"AstraZeneca's operating cash flow jumped 24% in the first half of 2009, allowing the company to retire $3 billion in debt since the end of 2008.

This post is part of a special annual report -- Top Stock Picks '09 -- in which TheStockAdvisors.com asked 75 leading newsletter advisors to select their favorite investment for the new year.

Gregg Early focuses on finding long-term growth opportunities among companies that specialize in niche, advanced technologies.

In his The New Tech Investor, he looks to AeroVironment (NASDAQ: AVAV) -- which is involved in innovative ventures in both wind power and unmanned vehicles -- as his favorite investment idea for the coming year.

"Two things make AeroVironment a unique company: its story and its stock price during the past year.

"The company has four divisions that by themselves seem very incongruous for moving the whole forward. It has a division that makes some of the most highly lauded and in-demand micro-unmanned aerial vehicles (UAVs) in service today.

"It also has a clean energy systems division that's best known for its 'architectural wind' turbines for urban settings, that are installed on manufacturing plants as well as office and apartment buildings.

"Its latter two division are the congruent in direction: one builds electric vehicle (EV) supply systems and the other supplies EV test systems.

"Investors should be well rewarded in the coming years by buying with major U.S. defense companies at current prices," says Gregory Dorsey.

The contributing editor to Stephen Leeb's Income Performance Letter explains, "The U.S. has more than doubled our sales of armaments to foreign nations over the past three years. And regardless of who wins the election, we expect this to continue."

"We're adding one for growth and income to our portfolio now. Lockheed Martin (NYSE: LMT) is a premier defense contractor. It's best known for its fighter jets.

"For example, Lockheed is now developing the F-35, also known as the Joint Strike Fighter, the replacement for the current generation of front-line fighters.

"But the company is actually engaged in four broad business areas, each of which should enjoy strong growth for years to come.

"As my high school football coach always quipped, 'Offense may win fans, but defense wins games,'" says leading growth stock expert Louis Basenese.

Here, the Oxford Club associate investment director takes a look at his three favorite defense stocks, noting, "When it comes to investing in the current environment, I'm convinced that you can't go wrong with this trio of companies."

"In my view, this sector willl never fall out of favor. The recent development with Russia serves to underscore another point I've been making for years. We always have to be prepared.

"Or, put another way, there will never be a good time for defense cuts, lest we want to leave our country vulnerable.Add it all up, and we can expect defense companies to enjoy steady demand. Even in the face of a recession.

"As the CEO of Rockwell notes, there has been absolutely no fallout in the defense industry as a result of the worldwide credit meltdown or other economic woes. So here's a quick run-down on the three defense companies we prefer for investors.

"Flir Systems Inc. (NASDAQ: FLIR) provides thermal-imaging and infrared camera equipment for military, law enforcement, and commercial applications," notes Leo Fasciocco.

In his Ticker Tape Digest, which focuses on stocks showing technical breakouts, he explains, "FLIR has convincingly broken out from a five-week base; the move was boosted by the win of a $359 million contract from the Army."

"FLIR, with annual revenues of $855 million, has been a sensational winner since 2001. It is a beneficiary of the war on terror and the need for equipment to combat it via military and security needs.

"Short-term, the daily chart shows the stock crossing its resistance line at 35.54. The move sends the stock over not only near-term resistance but also over the peak made back in early November. The action indicated very astute institutional buying.

"The recent fits and spasms of the stock market predict tough times ahead; and ironically, that's good news for Raytheon (NYSE: RTN)," says Louis Basenese, Oxford Club Associate Investment Director.

In The Oxford Insight, he notes, "When stocks are anticipating a recession, the best offense is often defense stocks -- and there's plenty of reason to expect this defense contractor to shine, even if a recession is confirmed."

"Defense will likely remain one of the largest budget items for the United States, regardless of which political party wins the fall election. And, according to JP Morgan Securities, the defense outlays of the United States actually increase, by an average of 6.5% during recession years since 1945.

"So in the end, recession or not, as the world's fifth largest defense contractor, Raytheon's sure to enjoy steady demand.

"I'm sure you've recently read, all about the large spy satellite that became disabled and was poised to re-enter earth's atmosphere with a dangerous load of toxic fuel. What few know is that Raytheon's Standard Missile-3 was specially modified to intercept the target 153 miles over the Pacific Ocean.