To the OP, I'm glad you don't have any regrets, and I don't either. I got mine back in March after letting my Sammy Focus go. I couldn't deal with its snotty build anymore. Now I'm a proud owner of an iPhone 4 and I'll be in a prime location to cop an iPhone 6 or whatever it's called with LTE once the technology has evolved to include good battery life (which I'm sure Apple will make sure of) and AT&T actually rolls out an LTE network. I'll have to keep a GSM carrier for the GSM unlocked phone.
I had a iPhone 3G and I'm so glad I was able to skip the iPhone 3GS because, although I know it's a fine phone, it wasn't worthy an upgrade after just a year on the early upgrade pricing, when some of the features I could get with the 3GS sans the speed and processor I had with my jailbroken 3G. Staying on 3.1.3 with the 3G allowed me to buy time and still enjoy my device while I explored WP7 (it'll finally be ready with Mango) and get the iPhone 4 when ready. I don't think us happy iPhone 4 owners will skip a beat the next several months...