I have about 20 themes installed atm ...however none of them will last long - except Sputnik. That theme is just *** eye candy, and that a matching Windowblinds skin is available is a must for me when selecting a theme - but most of all, Sputnik is very productive and effective.

My second favorite is UniverseMetal, but I really miss a
matching Windowblinds skin for it ;/

Other one I would probably use is Garam Masala if just a matching Windowblinds skin excisted.