I've been a fan of the SSB series since 1999 (just a little after its release). A friend of mine had the game and whenever I went over his house, we'd just sit there and play it for hours upon hours--too much fun. xD I never actually owned a copy of SSB64 for myself until many years afterwards though.
Melee was something I never really got into though. Nothing against the game, in fact I like it, but when it came out I didn't have a GameCube at the time, and when I got one I started playing other games instead. For whatever reason, Melee just never "stuck" to me I guess.
I started playing Super Smash Bros Brawl in June 2010 when my brother and I decided to buy it. As you can see from the picture on the side, I main Marth, and the story behind why I chose Marth as my main is kind of a funny one. This starts before we actually bought the game. So anyways, it might help to know that my brother is always reading up on various video games; reviews, ratings, etc. even if he has no real intention on actually buying the game--I guess it's sort of a hobby with him. This particular time he was reading up on stuff about SSBB and as he would look at various cutscenes and he would show them to me if he came across ones he really liked and thought I'd enjoy. Well one of the videos he happened to show me was the Marth vs Meta Knight (the video on the side) scene. Now at the time, I didn't know who Marth nor Meta Knight was, but I was really impressed by the video nonetheless. And that's pretty much when it happened. I liked Marth's 'performance' (I guess you could say?) in the video so much so that because of that video, despite me not knowing anything else about him, I thought Marth was an awesome character and that's when I decided when we get the the game he would be my main. Almost all because of just that one video. xD Funnier thing is that I have never once switched my main from Marth. I've had various secondaries from time to time (though I almost never use secondaries anyways) but Marth has always been my main.
Brawl was pretty fun for a while (still is though) but I kinda got bored with it after a while so I stopped playing it for a few months. Though, after that period of time of me not playing, I wanted to pick up the game again but I wanted to somehow make the game a bit more enjoyable than it was before. I started looking up Brawl textures and that's when I stumbled upon the BrawlVault (Kitty Corp: Meow Mix) and saw some really cool stuff there. I knew nothing about using textures then, so I pretty much had to start at ground zero. Through KC:MM, YouTube tutorials, other online guides, and much confusion and frustration I finally learned how to use textures. I actually went a long time (perhaps a year, give or take) without a KC:MM account--the only thing I did was download textures and use them. It wasn't until fairly recently that I made an account and started uploading my own textures.
Soooo yeah, that's pretty much how I got started with Brawl and doing the stuff I do now. :)