| Re: What program to design chips?
I use Illustrator for the basic design, and then bring it into Photoshop for the actual printing. Because my design uses special brushes in Illustrator (a variable-opacity "flame" brush that I designed myself), it takes forever for Illustrator to rasterize the image. I can bring it into Photoshop, repeat the image multiple times for the printing sheet, and then print them out a lot more quickly than if I tried to print right out of Illustrator.
Generally speaking (and particularly if the design weren't too complex), I'd definitely go with Illustrator over Photoshop for initial design -- you've just got a lot more control over the drawing itself. You can do a lot of the same thing in Photoshop (filled vector paths, etc.), but it's a lot less intuitive, and you don't have the same number of tools to work with.
That said, I did use Photoshop for one of my initial designs, but decided I wanted a "cleaner" look in the end, and recreated my design in Illustrator. I was just going to post the final chip design in the gallery, but maybe I'll also put in some of the interim designs as well...  | 
