Dude, are you kidding me? I've been playing Melee since DAY 1, and I play religiously. I play just about everyday, usually for a few hours. Yet, I continue to find new things I never saw before. I continue to learn different things about the game. Seriously, if Melee is that huge, I can't even begin to imagine all the stuff in Brawl.
Let's put it this way... Have you read every single trophy? Have you done it recently enough so that you know what all the trophies are from? Here's a big question: Have you ever used an Action Replay to play multiplayer on the target stages? Have you played on the debug stage with the picture of the bar in the background? Have you played 6-player Melee with 3 friends yet?
There's probably a lot you and I have not explored in just Melee. If they gave us an EPIC update everyday, and didn't release the game for another two years, we might know 30% of it. But as it stands, I've been playing their older game everyday for six years, spending hours on end with it, and I still find new, cool things. (For example, today I found out that Peach's trophy has rendered panties under her dress. XP)
~Dac