[ZombieBerry]

I use different icon sets in my theme, depending on what the focus is going to be.

I'll admit that a cool background and the same icon set does not a theme make, but for most users they just want to switch it up. There are themes where the layout of the screen or icons included are very different from stock themes.

You just have to know where to get them, or like Motorcycle Mama posted, make one yourself. Themes are pretty basic, or they can be as complicated as you want.

The only exception right now are Themes for OS 7.x.x.xxx devices that require a few extra steps and require a more in depth knowledge of Themes.