I'm split. I don't actually own a PS3 (yet), but I like that the best out of every option listed. Second favorite would have to be PC ('cause of Warcraft and awesome FPS like Half-Life and Source, not to mention if you keep up on it, it tends to look a whole shitload better than half of the current console games) and thirdly is my trusty old PSP. I love that little thing. Heh, I do half of my GW posting on it; the only bad thing is is that I haven't bought any games for it since Rainbow Six Vegas (which I've beaten multiple times over now, on every difficulty, plus all extra content). I did have MGS: Portable Ops and I loved it, but some damned fool had to smash the UMD. I miss my awesome online multiplayer.
The big thing I'm waiting for is MGS4. I've been a Kojima-fan ever since MGS for the Playstation, and goddamnit, I can't wait to pick the story back up. It'll be interesting to see what Snake's up to, and what hype is true.