I'd like to share what info I have now on what I've observed of the 3 consoles thus far. For the record I have a 360 and am camping out for a Wii which I am most excited for. I might get a PS3 if anything for a fancy Linux box to develop on and for possibly any exclusives.
Xbox360:
Advantages:
1. More great titles coming out faster this generation than the Xbox had.
2. Xbox Live netplay runs great even with little bandwidth use and headset talking between multiple players.
3. Achivements increase the overall replay value and make a player strive towards greater goals.
4. Has many special features such as USB devices can be used (I use my flash drive to play music on the 360 in games) and connectivity with Windows Media Player or Windows Vista.
5. Emulated support (albiet poor) of original Xbox.
Disadvantages:
1. Achievements are really just an alternate form of e-dickery. After a while most people realize some of it's bigger flaws (for example: easy gamer point farming from rented titles)
2. The connectivity with various programs via a network seem like a huge money scheme. The Vista features could easily be put into a program in older Windows versions, however give more reason for a user to upgrade their OS. Sadly I'm more of a Linux user now and don't feel any of the features as too outstanding enough to switch back or worse upgrade to Vista.
3. Various hardware problems with durability. Apparently heats up a lot. If you keep it vertical though most of the heating problems are averted.
4. (See Playstation 3's #3 disadvantage)
Playstation 3:
Advantages:
1. Blu-ray. If you're into that.
2. Can be used as a computer. BIG advantage here. Need a new PC, but don't care if it's running Linux (or hell in my case prefer it)? A $600 powerful console/computer really is a grand deal when you put it in those terms. A PC alone of that cost now is usually on the low end. And would't be able to play Playstation 3 games by the way
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3. Emulated support of Playstation and Playstation 2.
4. PSP connectivity and possibly some other unknown extra features.
Disadvantages:
1. Blu-ray. If you're not into it and hate how it's a big reason the PS3 is putting a dent into your wallet.
2. The online mode is apparently nothing special by any means or even comparable with Xbox Live's service. Reports say it's more like PS2 online with a few touchups and features. Very disappointing news.
3. Comparable with the Xbox360 as far as graphics, most don't see the difference. And a lot that do actually don't seem to care. "Graphics are nice, but we're hitting a peak where really flashy things can still be seen on low-powered machines and are more determined on the developement of the game."
4. Seems to have less exclusives than first percieved. Assassin's Creed is going to be multiplatform. Resident Evil 5 and Devil May Cry 4 were now announced by Capcom as not being exclusives. Even Kojima has considered putting Metal Gear Solid 4 on another console by saying "At least it would be doable to port it to the Xbox360 as it's powerful enough" [By the way excuse me for being short on sources here so if anyone wishes to correct me then by all means go for it or help as I know I'm not completely full of it here].
Wii:
Advantages:
1. New controller that can determine where it is in a 3D space at all times. Has caught a lot of attention.
2. Virtual Console let's you revisit a lot of your favorite classics for cheap. Including hit games from consoles like the Famicom/NES, Megadrive/Genesis, TG16, SF/SNES, and Nintendo 64.
3. Backwords compatibility with the GameCube (the only console with native backwords compatibility this generation apparently).
4. Low-power, small, durable.
5. Some extra features such as DS connectivity, internet browsing, and possibly some unknown stuff.
6. The price. $250 is a really hot deal considering the other 2 are $400 and $600 (No, I'm not counting the core models. I don't think anyone should. They are stripped of too many features).
Disadvantages:
1. Perhaps you care about graphics. Just bought a sweet new 1080p television and it's the only console that doesn't do anything beyond a measly 480p. Bet it would be a real let down. That aside from it being somewhere [blind guess] about 5x less powerful than the other 2 consoles.
2. ITS MADE FOR KIDS LOL; no but seriously it's 4 days away there's one more disadvantage for you. Can someone help me think of another?