• Buy Google, Inc. (NASDAQ: GOOG). Mandel believes that Google's growth potential is not fully understood by investors because its core market of paid search is still in "its early innings." I don't know Mandel's earnings forecasts for GOOG; however it trades at a moderate PEG of 1.38 -- reflecting a P/E of 43.3 on 24 analysts' consensus 2008 earnings growth of 31.4% to $17.45.
• Buy Coal -- e.g., Peabody Energy Corp. (NYSE: BTU). Ross is high on coal which is a very out-of-favor industry due to a current inventory glut which he thinks will be corrected by the fourth quarter of 2007. He thinks that coal will gain a larger share of electricity generation. While acknowledging the environmental issues, he thinks that coal could be made clean. He also predicted that Congress would not do anything punitive. "If they do, the public will have to choose between green and lights out." BTU is one I think is worth examining -- it trades at a screamingly cheap PEG of 0.66 -- reflecting a P/E of 25.8 on 17 analysts' consensus 2008 earnings growth of 38.9% to $3.43.
• Short Ambac Financial Group, Inc. (NYSE: ABK) and MBIA, Inc. (NYSE: MBI). Ackman attributes the meltdown in the subprime mortgage market -- on which I've posted -- to Wall Street 's creation of collateralized debt obligations (CDOs) which buy up risky paper, pool it and make it less risky, in turn enabling more reckless lending. He highlighted the conflicted role of the rating agencies (they are paid to rate things, not to be right) and deconstructed the high levels of leverage and low capital bases underlying the two bond insurers -- ABK and MBI -- which Ackman has sold short. For example, Ackman argued that ABK has $18.7 billion in subprime exposure through guarantees of Mortgage Backed Securities (MBS) or CDOs which he estimates is 284% of its statutory capital -- an insurance industry measure of capital resources. He's betting that ABK and MBI will not have enough statutory capital to cover the losses on that subprime exposure.
• Short Macquarie Bank, Ltd. (ASX: MBL). Chanos likens this Australian bank to Enron. MBL has made money by raising big investment funds, using the money to overpay for acquisitions and selling to separate MBL entities -- capturing fees along the way. Like Enron, Chanos believes that MBL relies heavily on off-balance sheet financing and related-party transactions. Chanos also pointed out that MBL has a "cult-like devotion" among some investors and pays its people "lavishly." Chanos is betting that MBL will tumble as the private equity boom collapses.

Before putting any money into these ideas, make sure you avoid these six biggest investment mistakes. I know that's easier said than done but if you have questions, leave a comment.

Peter Cohan is President of Peter S. Cohan & Associates, a management consulting and venture capital firm. He also teaches management at Babson College and edits The Cohan Letter. He has no financial interest in the securities mentioned in this post.