i honestly don't like SSB. At least it doesn't appeal to me. The only one I truly liked was the N64 one. SSBM was an ADD fest to me. Maybe I'm getting older, but its too fast and flashy for me.
I got SSB:M because it was bundled in with my GCN.
I'm one of those Wii owners that isn't a ::marioboy:: as crazzyman likes to point out. In fact, other than Mario Golf (which I actually didn't buy), and the Lost Levels on my Virtual Console, I have never bought a Mario game (besides the SSB games). SMB on NES was bundled and I was like 6 at the time so that don't count either.
And I probably won't get SMG since I can just borrow it from everyone else.