I got a 3G (the "touch button" version) for Xmas a couple of years ago and love it - I'm trying to decide now whether to upgrade to the nano or video version.

1. They don't make the mini anymore, but you can still get them all over (meaning, they're cheaper). The nano is smaller (especially thinner), has a color screen, displays photos, and uses 2 or 4 GB of flash memory instead of a 4-6 GB hard drive. Mini is brushed aluminum (choice of 5 colors) and nano is black or white plastic front, chrome back.

2. Apple doesn't allow many discounts on new products, so you'll be lucky to find a sale price for more than about $5 off. If you buy the nano direct from Apple you can get the back engraved free. (If you're in school, Apple has educational discounts too!)

dealmac.com usually lists the best available prices for all iPods.

HTH.