There have been a number of one shot characters I'll never play again, or at least I probably won't... It's not like I'd turn down the chance to play them again. Even the dead ones.
One I probably will never bring to the table is Graywolf the Archmage, my 23rd level Rules Cyclopedia magic-user from when I was 11-13 years old.
Here are some pics from his character record book.