well for starters 360 and ps3 both give you more bang for your buck (bigger value) hdtv goes awesome with 360 and if your a hardcorish gamer then you should go with 360, plus there are super awesome titles spanning all genres out already so they got whatever your interested in, plus im sure you have plenty of buddies to play on xbox live with <--great service, + you can rent HD movies off of xbox live
wii provides more fun if you like to game with friends most of the time, its more revolved around that and not so much hardcore, but dose have promising titles in the future, but getting one now only gives you trills for so long because of the lack of games (so if your planning on getting more nex gen consoles in the future, this should be your second choice)
ps3 dosent have the great software but also promises to deliver with great titles right around the bend, cool psp support if you have one and solid features such as a blu ray player for your hd needs, all though a lot of it is a bit weak right now, in time it will bloom into what its meant to be, a hardcore all in 1 entertainment system, and if you cant already, im sure it will implenent all the features xbox live offers you sooner or later (such as renting hd movies and what not) but it probably wont get as good as xbox live overall
hope i could help