If we are talking only ones that have been played, here we go.
Shadowrun: Shades. I started him back in 95 during a demo at a local con called BASH Con. Back then, he was a basic razorguy who shot things with a look similar to Grifter from WILD Cats. Anyway, I didnt care for the character as written, but liked the style and when I found a regular group I remade him as a Merc/PhysAd. I played him in 2nd Ed for about five years and he got pretty up there, being the only origional character from the group to survive. When we transferred over to 3rd Ed, the new GM and origional group memeber whos own PC was Shade's best chummer, let me convert him WHOA. I ende up with some MAD stats and wicked speed/initiative. Not to mention I had enough karma to get initiate level four...yes FOUR. I played him for a few more years, rounding out skills and eventualy having to retire him. What I like about him is that his personality shadowed and grew with my own. At fiirst he was nothing more than a hired gun with a lot of ange issues. But evetually, he found things to fight for and instead of playin by other people's rules and doing their dity work, HE was making the rules. I currenty use him as my major fixer NPC in my games
Star Wars (WEG) Ric "Hawk" Hawkins. Ric was a simple brash pilot and was perfectly content flyin a snubfighter/Freighter/etc, in the litte Rebel SpecOps team we had...but NOOOOO, the damn GM just had to have a force user to mess with. So one random roll later, and faster than you can say "Corran WHO?" (Damn you Michael Stackpole!) poor Ric was suddenly Force sensative. The first team all but bought it on Ryloth, and only Ric and two others out of seven survived (hmmm deja vu). We almost ended the campaign, but said GM was reading the X-wing series and guess what..Knight Squadron was born, with Ric, a newly minted "Commander" and jokingly called "the next Skywalker" (but not to his face) in command. What made it fun wasnt the spacebattles, (but they were fun) but it was the rest of the squad and their antics and poor me not able to do what I REALLY wanted to do...Damn dark side.