After posting yesterday that I was going to be responsible and wait a few weeks before getting a iPhone 3Gs, I ended up running out and getting one this morning when I found out the nearest Apple store had some still in stock. I got a 32 gig black model. I haven't used it much, but first impressions are pretty fabulous. Video looks good, touch-to-focus works really well, camera does much better in low-light, and sound quality seems to be better. But the biggest difference you notice is how snappy everything is. Apps launch faster, the keyboard responds quicker and never hiccups.
I'll post my full impressions after I've had a day or two to play with it, but I'm really excited to see what people do with this new hardware. I think we're going to see some awesome games and other programs before long.