I know what my previous names were, but I'm not uttering them (too obscure, not really that good, but not embarrassing). I can't remember if I started going by Eriol with EQ1 (definitely by then), or sometime in my early Starcraft days.
My first online handle was in the early 80's, when hacking cracking and phreaking was all the rage. It was Kracker Jax. I thought it was such a K001 and edgy handle...along with all the million of other junior high kids who took on some variation of the name.