Neither, I'm keeping my 16GB version1 until a 32GB model comes out- no good reason not to. I have a fine GPS, and email doesn't come faster in 3G . All new Games and programs (except some minor GPS related) will be available with firmware 2.0 on Version1. Apple blew it with such minor updates.
8gb for me. I don't really use it as an ipod, just for the short <10 minute walks to class, so at most I have about 50 songs on it, and I don't use it for movies. I have my ipod with all my music in my car already.
Well, not buying the new phone this time around, maybe the next version. So, I picked the "not buying 3G iphone" choice. If I had to, I would choose the 16GB since you can get white.