Started with Red Box Basic, extending out to Expert. It was amazing because role playing games .. er, game, was a new amazing concept.
Played some AD&D. Played a heck of a lot AD&D. Had the most time and freedom to play. Lots and lots of AD&D, most of any edition. At the end we were using all the Skills and Powers books, we were such twinks but the DM had all the monsters. It was my favorite edition at the time. (And did I mention I played a lot of it?)
Played a good amount of 3.0 and 3.5, ran more of both - these were the editions that I DMed the most of all of them. They brought so much new, they became my new favorite edition. Until I burned out DMing it - too much prep.
Played a good amount of 4e, never ran it outside some one shots. I didn't start playing 4e until it was out for a while, so never got the "just core books" experience. Eventually played with Essentials mixed into the rest.
In a little tangent to other d20, I ran 13th Age for four and a half years. It's my favorite D&D-like system.
I playtested Next, and have done a good amount of 5e. It's my favorite edition of D&D, but my tastes have changed over the years.