I tried my hand at textures a few nights ago:
http://killpixel.com/textest.jpg
From a picture of a rusty baking pan, I cut out horizontal bars and applied bevel/emboss to each one.
The cool part is you just use the eraser to make the worn/distressed bits and the bevel/emboss as automatically applied.
Slap on some grime and blend as you wish, shrink, sharpen, adjust hue/saturation and brightness contrast, index to quake palette and BAM, speedy textures.
This set took about 1.5 hours total.
Now that I know how to make textures I'm going to experiment with less generic designs.