I have the iPhone 3GS, the ONLY thing that appeals to me about the 4 is the front and back cameras and the "Face Time" app, but I don't feel "I gotta have it"
Same will go for the 5 when it hits, when I'm up for a "free (or cheap) upgrade I'll move up to whatever, but I'm really in no big ass rush.
I still hate the fact that in order to dev for their App store I MUST have a mac (or a hackintosh)
-Loki-