I'm upgrading for the original iPhone, so I'm going with 3G! I'm getting consistent 2.2Mbps speeds around here, although I did find a nice 3G dead zone where it was back to EDGE. I'm guessing it's a rogue cell tower that hasn't been upgraded.
GPS is also great. I'm going to try geocache hunting tomorrow. I bought the Geocaching app that's $9.99 and signed up on the Web site. It'll get my azz outta the house and it sounds fun.
The internal guts are also awesome. It is zipper doing everything. It's like trading in a G5 PowerBook for one of the new C2D 15" MacBook Pros.
I also can tell the still camera is a huge upgrade, if nothing else for the auto zoom. It's still hard to take a picture of a puppy who won't stay still, but my other shots that have focused are a lot clearer. Video? Jury is out, but it seems great. I just don't understand how to sync it with my computer very well. iPhoto imported it as a frame grab, not a video. I thought maybe it would sync with iTunes. If anybody knows how to help me on this, please do!
I almost forgot about the 32GB of storage. I can't just dump all of my songs on there like I did a few years ago with my 30GB iPod, but I have at least twice as many and have dumped a few movies, a lot of music videos, and some TV shows on there. Oodles of Family Guy on my iPhone. Freakin' sweet.