Base your choice on usage.
If you just use the iPod at the gym or riding the bus consider a nano. Smaller more compact. Nice if you get one of those arm bands for while you're at the gym. Good for mixes and individual songs.
Standard iPod/iPod video - larger storage. Better for full length album listening. Good if you listen a lot in your car or at work. Good if you have a docking station at home/work or auxiliary port on your deck in the car.
I’ve had good experience with the ipod 30 gig video, the 2 gig nano, and the old shuffle. All different and all good if you match them to your need.
