Here's a general rundown of my opinions of the major consoles, handhelds, and the PC:
PC: Best thing to play video games on, IMO. It has better graphics, more precise controls, and is just all round better, except for one thing. Simplicity. I tend to get RPGs and other single-player games on here.
X360: Best multiplayer. So much simpler than on the PC... matchmaking, choose match, ok ready to go! Instead of painstakingly finding the right server... PSN is good, too, but there's just way more people on Xbox Live. Until recently, the 360 had better exclusives, too, (they still get some, but mostly shared with PC) but the PS3 is making a HUGE comeback. I get my multiplayer, esp. shooters, and action games like Assassin's Creed. Also, for some reason I feel like getting Bioshock on it. Atmosphere is better on my 50'', I guess.
PS3: Dang, I want one. It has a higher hardware potential (graphics esp.) than the 360, and has come out with some REALLY good exclusives lately, including Uncharted 2: Among Thieves, the generally accepted GotY last year, and God of War III (can't call it GoWIII any more...), one of the contenders for that award this year. (I think Mass Effect 2 is going to win, personally)
Wii: Full of squandered potential. Nintendo's hardcore games don't even pretend to use the motion controls that much, (except for Metroid Prime, I've heard) so it's up to the 3rd person games. Sadly, most of them just haven't cut it. Motion Plus is a TON better, but most developers seem to have moved on to bigger and better things. For now, it's just something to play the next Mario and Zelda on.
DS: See above, except less hardcore Nintendo games. (not counting the everpresent Pokemon) There ARE quite a few really good games on here, but they're hard to find. Square Enix seems to do quite well on here, with half a dozen or so FF games, and the new Kingdom Hearts. (Still haven't played that...)
PSP: Exactly what it's called, Playstation Portable. It uses discs (sort of), and it even has a control stick. I just prefer the Gameboy's style of games. Which leads to...
iPhone: I just had to put it in here, say something about it. Ultimate time-killer. Nothing as satisfying on any of the other consoles, even the DS, just a bunch of games that I could play clones of (or even the same game) for free online. Flash FTW!