People saying the N64 is the best are probably just nostalgic. Melee improves on everything. Brawl not so much.
Melee was more fast-paced and it didn't have those totally unbalanced ultimates (though I know you can turn them off but the character's abilities have been balanced so that if they have weaker moves in general their ultimate will be a bit stronger).
And I'm just mad they totally blew Sheik in Brawl. And Kirby.