5. Crytek UK
Why? I think you all know why I named them. Most of the staff here used to work at Rare. They could revive Perfect Dark, and make that long-awaited Conker sequel.
This would be perfect. MS has a large budget, but lacks the ability to make anything outside of very western games (Shooters, Racing games, RPG's, and Party titles). Conker's Bad Fur Day was a platformer, it appealed outside of the US greatly, and Conker is a damn good mascot to brand the 360 with.
If most of Rare moved onto Crytek, then MS should definatly buy them. They could make a damn good Conker Platformer, maybe a sick ass fighting Killer Instinct, or a great shooter like Perfect Dark, or maybe a whole new IP. Also Banjo Kazooie, finally a game kids can play! MS could compete against Nintendo for once.
Finally MS could bring more diversity in with their games! They already do a damn good job on shooters nad racing games.
Also Mistwalkers is a good idea, but that would be a tough buy. The guy who invented Final Fantasy seems to me like he makes games out of passion, not money. It would make more sense to work with with Square Enix, Namco, Atlus, and Mistwalker, and force any PS3 JRPG exclusive to go multiplatform.
Crytek and Epic games are 2 damn good options. If not them, then maybe Silicon Knights (Eternal Darkness, Too Human), or something new. Nintendo helped develop Retro Studios, and that's been one of their most successful studios yet (Metroid Prime franchise and Donkey Kong Country Returns). Maybe MS could follow by developing a studio in Japan themselves.