Didn't think I'd see another technical writer here! It's a pretty obscure job all in all. We're in very similar positions, too. I used to write a lot for fun, but writing all day at work kind of douses the flame, so I started using music to FULFILL MY MANLY NEEDS instead. Actually, sounds like your work is slightly more interesting than mine. I just write instructional stuff, which gets pretty dry after a while.
Anyway, tech writer five! *smack*
Tech writers unite!
But yeah, writing boring stuff all day definitely douses the flames of writing desire. I get my creative kicks from music nowadays. It's cool--nobody invites short story writers to rock out in clubs, haha.