Bright and early this morning, Goldman Sachs downgraded gaming guru Activision Blizzard (NASDAQ: ATVI) from Conviction Buy to Buy. In a note to clients, the brokerage firm explained that it sees greater relative potential for near-term price appreciation in other stocks. Goldman maintains a six-month price target of $16 on ATVI, implying expected upside of more than 29% from the shares' closing price on Wednesday.

ATVI is a ripe target for downgrades, if only because analysts are so lopsidedly optimistic toward the "Guitar Hero" parent. Zacks reports that the equity has attracted no fewer than 18 Strong Buy recommendations, plus two Buys -- with not a single Hold, Sell, or Strong Sell to be found.

Tech stock VMware, Inc. (NYSE: VMW) is broadly higher today on the heels of an upbeat note from Goldman Sachs. VMW was added to the brokerage firm's Conviction Buy list, with Goldman noting an expected boost in sales. The firm also thinks that VMW is better-positioned than many of its competitors to ride out the economic recession.

In addition to the Conviction Buy nod, Goldman also hiked its price target on VMW to $29, representing a premium of 22.8% to the equity's Tuesday closing price. The stock could attract additional price-target increases during the short term, as Thomson Reuters pegs its average 12-month target from analysts as $23.31 -- a modest discount to yesterday's close.

Goldman Sachs shook up its ratings on the oil-services sector today, and made a notable adjustment to its "conviction buy" list -- Halliburton (NYSE: HAL) was ousted from the roster in favor of Transocean Inc. (NYSE: RIG). The brokerage firm still maintains a "buy" rating on HAL, but it's pretty obvious that the stock is now playing Jan Brady to RIG's Marcia.

So, why does Goldman prefer RIG to HAL? The former is more strongly levered to oil than the latter -- and, going forward, the analysts expect strong fundamentals and heightened oil prices to support "oilier" stocks. In a note to clients, Goldman said, "... we continue to expect a healthy oil-services spending environment through 2010, supported by low reinvestment rates and secular trends to more complex, high-margin drilling services."

Despite the bullish "buy" ratings on both securities, Goldman tempered its optimism by trimming its price targets on the duo. HAL's forecast was slashed from $63 to $58, while RIG's was trimmed from $189 to $178. The new price targets represent a 44.5% premium from HAL's closing price yesterday, and a 47% increase from RIG's Thursday settlement.