Mine is a combo. Back in college, my AOL IM handle was box2344 (the P.O. Box address for Jackson guitars at the time). Then I changed it to Stop35, which was the name of the rest stop halfway between my home town and Penn State. In later years I combined the two, down to "boxstop", and added "7" as it's my favorite number. Hence, boxstop7.
To HANGAR18 and Raven17 - I'm also a huge, huge, huge, HUGE Megadeth fan. By far my favorite band; Megadeth is the reason I picked up a guitar, and if one day I'm even half as good as the likes of Mustaine, Broderick, Poland and Friedman, I'll die happy!