Naughty Dog- Obvious, ain't it? Such a great company when it comes to graphical and story-telling achievements. They are a little clunky on game play yet, but I still have high hopes for them.
Favorite Game: Jak 2
Sucker Punch- They made one of my favorite series (the Sly Cooper series) on the PS2. They also have developed the Infamous series over these past few years, which are great in terms of the sandbox style of game play and, when it comes to character development, they are in a class of their own.
Favorite Game: Infamous 2
Sony Santa Monica- God of War. There you go.
Favorite Game: God of War III
Square-Enix- Despite some very questionable decisions these past few years, their legacy in the JRPG genre is almost unmatched. They are a graphical juggernaut and have also produced some of the most beautiful soundtracks I've ever heard from any video game company.
Favorite Game: Final Fantasy VIII
Namco-Bandai- I mostly like them just for their work in the Tekken series, but they are a powerhouse when it comes to producing some of the best fighting games out there.
Favorite Game: Tekken Tag Tournament 2
Insomniac Games- They made the original Spyro games before the rights were sold off to Activision and they made the Ratchet and Clank series. They're mainly on this list for the latter and the fact that they did not sell out to become a console-based company.
Favorite Game: Ratchet and Clank: Going Commando