Wii is a lot of fun when you're playing with your friends. Very fun with sports games. Not a very "serious" console, if you catch my drift.
PS3 IMO is the best for sports games, and 360 is the best for shooter games. Mostly because of the selection of games for each console.
As far as potential goes, 360 has the upper hand now, but PS3 has a lot more to work with in the long run.