Looking back at the themes, I see there have been some really sucky ones. I remember viewers being perplexed by "Unbelievably Small" and "Ain'ts and Saints", just to name two. Happily, I think there have been more good themes than bad ones.
Another thing I noticed is that some of the older themes were really broad. "Guy Names", for example. Or "Love". I attribute that to my smaller music collection at the time, plus fewer viewers, and fewer musically astute viewers back then. Heck, the host was less musically astute. I've broadened my musical knowledge considerably over the past five or six years.
I'd be interested to hear what themes you particularly liked and/or would like me to do again. I try to keep the cast fresh, but there's no reason we can't redo a theme from two or three or four years ago. Just don't ask for a repeat of "Ain't and Saints"! That one will never see the light of day again!