SSB64 is what got me heavily into video games, and in particular Nintendo.
I'd just moved house to the opposite side of my country and was struggling to fit in with the locals. I spoke too 'poshly', and everyone thought I was snobbish as a result. I finally made friends with a pair of twins who had got a N64. I didn't know much about Nintendo video games but Pokemon was just taking off and I knew about Mario a bit, so when they invited me to play Smash 64 I joined them.
It was amazing. Even as someone who hadn't grown up with Nintendo(was raised on Sega originally although had played SMB2 around my cousin's house) I appreciated what a ground breaking idea of having all the biggest and brightest Nintendo stars beating the ever loving crap out of one another.
I was god awful at it, but we played every week for the next two years together, and likewise when Melee came out we began playing that on a weekly basis. By the time Melee had rolled around I'd gotten the Gamecube, and more importantly gotten to the stage where I presented a challenge. We all still join up once every two weeks to break into Brawl and Melee sessions even to this day.
Melee incidentally is my favourite, due to it's superior speed, but Brawl allowed all three of us to play on a level playing field and it's usually anyone's game these days.
Sorry to divulge, but I've been around since Smash 64, and absolutely love Melee.