I have used Duality(it sucks) and themer (themes won't load)Originally posted by mc68k
ResExcellence has some great hacks to keep busy for a while. I don't know of any place that offers dock pdfs. I think most people go transparent.
Visage is also a good shareware program for replacing pdfs, poofs, boot panels. etc.
There are also theme editors (Duality, MetamorphX, Themer etc.) that can change the appearance of OS X sort of like Kaleidoscope for OS 9 and earlier.