This is one area that Windows Mobile has it in spades over the (nonjailbroken) iPhone – the ability to customize it. I love my iPhone, but being a work phone I know that I'm stuck with using it “Steve's way.” When I had my AT&T Tilt (HTC Kaiser, I think), I did play with one other skin once, but I forget what that was. The phone got a bit wonky, so I did a restore back to factory defaults.