i've had a lot of different iPods. if you are the type of person who would never need to listen to more than 700 or 800 songs (aka, not your entire music collection), then I'd say go with the Nano, which I have.
But if you want an ipod because you want to have every song you own with you at all times then go with a ultra reduced priced iPod photo, 30GB.
HOWEVER, if you think you will wan to watch TV shows on-the-go on an incredibly tiny screen, then I say go with the new iPod video.
finally, if you could care less about a color screen and you don't mind having only about 700 songs with you, then I'd recommend getting the super awesome, virtually scratch proof, iPod mini.
hope this helps.