FYI, you can patch the uxthemes.dll file in XP for free (I think TGTsoft used to have a patcher, but I'm not sure if it works with SP1 or not ... there are patchers that do), and bypass stylexp.
Some of the themes out there are great
Check out my desktops @ messikan.com (also in my sig) I'm pretty happy with them 
Some of the themes out there are great