A great review of all 3 of the next gen consoles.
Wii
Pros
[+] - Nintendo games (Mario Galaxy, Metroid, Zelda)
[+] - Price (cheapest)
[+] - Multi-player / party games
[+] - Internet browser
[+] - Virtual console (SNES, NES, Megadrive and N64 titles for download)
[+] - Runaway leader in sales should prove attractive to developers
[+] - New control scheme - Resident Evil 4 and the upcoming Pro Evolution Soccer 2008 title utilise the wiimote really well
Cons
[-] - Not HD
[-] - No media capabilities
[-] - Not much in the way of serious third party support so far
[-] - Online matchplay is somewhat cumbersome
[-] - Not much more powerful than last generation of consoles (PS2, GC, Xbox)
[-] - New control scheme - some developers have thrown any old shit onto Wii to cash in on the success (Tony Hawk Proving Ground)
Key titles: Mario Galaxy, Metroid Prime: Corruption, Zelda: The Twilight Princess
360
Pros
[+] - Fantastic games line-up
[+] - Xbox Live - best online service by a distance
[+] - Marketplace - XBLA, Xbox games for download, HD movies,
[+] - HD
[+] - Massive software attach rate attractive for developers
[+] - Achievements / Gamerpoints - when used correctly, encourages extra play and prolongs life-time of a game
Cons
[-] - No HD movie playback as standard (HD-DVD player is £120 extra)
[-] - Not wireless as standard (£60 extra)
[-] - Xbox Live has a subcription fee (£40 per year)
[-] - Reliability (this has now been addressed somewhat - refer to forums for Falcon models if you go down this route)
[-] - Achievements / Gamerpoints - when used incorrectly
Key titles: Halo 3, Gears of War, Mass Effect, Bioshock, Call of Duty 4, Orange Box
PS3
Pros
[+] - Decent games line-up now. MGS4, GT5, Killzone 2 due in 2008. FFXIII probably 2009.
[+] - PSN - Free, Home due in 2008
[+] - PSN - PS1 games for download, additional content planned - Remote play with PSP
[+] - HD
[+] - Blu-ray out of the box
Cons
[-] - 40G model has no backwards compatibility
[-] - No wireless headset for voice-chat as standard
[-] - Price - most expensive
[-] - Worst seller of the three - might discourage some developers
Key titles: Uncharted, Motorstorm, Ratchet and Clank, Call of Duty 4, Resistance