Because Brawl is essentially Melee with moar levels, moar items, moar characters, and a stage editor (not an overly impressive stage editor, but still, IT'S A FREAKING STAGE EDITOR O:), I see no reason to vote for Melee unless you were a huge fan of Mewtwo, Dr. Mario, or Roy. So we're down to SSB and SSBB.
SSB was great, but the only thing it had over Melee was the Bumpers (seriously, did HAL actually think they could replace such an epic item with something as lame as the flipper?), a "board the platforms" bonus stage (cool, but not important), the level with the warp pipes (neat, but not much more important), giant-ass snorlaxen (did anyone else notice he seemed to have lost weight after the first game?), and nostalgia (I was going to say "oh, fuck, giant ass snorlax" here, but I decided to make that a seperate point altogether).
Brawl brought the Bumpers back, bringing SSB's selling points down to two unimportant points and one decent point, and Brawl has a shitload of other epicness, so Brawl wins my vote.