Rock Band 2 does have better songs, but it will probably benefit ps3/360 owners bcus Wii owners didnt get those features in rb1 and it is unlikely or maybe in rb2. it all comes down to the tracklist and rb2 probably has the better one plus all dlc will work.
so 360 = rb2
ps3 = rb2
wii = ghwt
Above I'm a proud Gran Turismo fan, not a Sony fanboy, and now a proud 360 owner, but sharing xbox live accts ATM
End of 2009 Predictions (made Jan 1, 2009): My predictions were pretty accurate, the 360 was over and the Wii was just under.
Wii: 65 mil (yea I'm crazy) 360: 35 mil (its getting there) PS3: 30 mil (the slim better do well)
End of 2010 Predictions (made Jan 7, 2010):
Wii: 81 mil 360: 47 mil PS3: 45 mil