there isn't a 'best' gaming console per se..each and everyone is different, and caters for different people. the wii is good to play on with your family where as the 360 and ps3 are 'maturer' consoles where you'd get a variety of games.
if u want a console purely for gaming go for the 360. it has tones of a++++ games, and a larger catalog of games overall over the ps3. online is much better as well but you have to pay for it. you get what you pay for. it is cheaper than the ps3. if you want to play online over wireless, you have to purchase all of that separately.
if you want to watch BR movies etc and want to play games as well then go for the ps3. it's an all round media system. where as the 360 is mainly for games, although you can watch HD-DVD's on there. online is free on the ps3 but not as good as 360's. wi-fi is built in which is a bonus.
GTA4 is available on both consoles but the 360 has extra content which is downloadable at a price (MS points). NFS is available on both consoles too.
ps. i'm not a fan boy.