I have a bunch that I cycle through. These are my faves:
OSX Zen (from Visto Themes - there are a bunch of OSX themes out there)
Chrono Zen
Precision Zen
Crackberry Abuser 2
Explorer
I think I got all of them here except the precision theme.
I won't bother posting pics, since the "what does your screen look like" thread pretty much covers that, but for smirks n giggles...
I'm a "cycler" too...
Precision
Halo
Black and White 8100
Pillar
All of these in Zen formation.
Posted from my CrackBerry at wapforums.crackberry.com
I think the best themes are the ones that are free. $7 is a ridiculous to pay for a GUI overlay. For every theme the author expects to get paid for, someone else has made the same for free.