I have played every edition of DnD over the years (although very little 3rd). Been mostly playing 4th ed the last couple of years.
Over my whole gaming career, which much be about 30 years now, have also played lots of Hero (various editions), Talislanta (various editions), most of the old TSR boxed games (Top Secret, Gamma World, Gangbusters, Star Frontiers. oh what I wouldn't give for a good 4th ed take on Star Frontiers), 1st and 2nd edtions of Shadowrun (of course), some Warhammer 40k, some Battletech, some Ars Magica in the 3rd to 4th edition era. Oh, and don't forget Dawn Patrol. When I was in junior high we were Dawn Patrol junkies. A little GURPS but didn't really care for it. A little bit of MERP but couldn't keep a group together.
And for the cherry on top, I once played Toon in a McDonalds with some of the geekiest geeks ever to draw breath. That has to the the Olympus Mons of utter gameing geekout.