Ive had my 32GB 3GS for about 6 hours now and love it! I came from a Curve 8900 and had a 3G before that and I'm sooooo happy to be back to the iPhone. I forgot how much I loved it! haha. The speed increase is noticeable from the 3G. The camera is amazing and compares to my Curve 8900's which had a amazing camera on it, and flash. My 3GS did get quite hot while doing its initial sync with iTunes and it was enough to spark the memory of reading peoples complains about the 3GS over heating, so I'm hoping that doesn't become a issue. Another big improvement and this is a pretty obvious one, is the increase in space. I really didnt think I'd need or care about having 32gbs of space, I was wrong, its amazing! I can have all of my music, music videos, pictures, apps and 10 full length movies all in my pocket, its really pretty amazing!
So far I'm very impressed, now was it worth $500, thats still questionable but I have a feeling I will be at peace with it sooner or later...