I got the black 16GB one last weekend. Stood outside the Regent Street store for all of, oooh, 5 minutes at 8:55am. Not many people waiting for one (three weeks after the launch...) and I got mine and walked out of the store within 40 minutes.
The girl who activated it was a bit useless and tried to use my credit card as a bank account by simply chopping the last eight digits off the 16-digit card number...

So I think I'd probably have gotten out of there within half an hour if she hadn't been hungover. Oh, and leopard-skin leggings, too. Eeek! (Her, not me.)
I don't think the colour is all that important. I have mine in an Incase rubbery case thing, so the back is covered all the time.
Just to finish off, I'm loving my iPhone 3Gesus. I love the fact that I can get my email anywhere (except on the Tube where you aren't allowed to move or speak, or, thanks to Transport for London, be cool). I love the App Store, and the freebies you can find on there. I think Apple have done a good job, and to be honest, some of the gripes people come out with are baseless.
- 2MP camera, no flash: I have a Canon Powershot G9 12.1MP camera for good shots. I wouldn't rely on my phone's camera anyway. A dedicated 5MP digital camera is much better than a 5MP phone camera any day.
- No MMS: I have email, and it works, and it's free. MMS costs around 35p per message on other tariffs.
- Battery life sucks: Well, I haven't experienced the need for a larger battery. I have it hooked up to a USB dock at work and at home, and I'm rarely more than an hour away from a computer anyway (I hate my life...)
- The keyboard is too difficult to use with my elephantitis fingers: Why is that Apple's fault? I prefer the on-screen keyboard to the 12-button keypads of yesteryear. Seriously, you need to remember where things are to press them on a Nokia. You need to remember that the 1 key is for . , ; : etc., and that these punctuation marks go in a certain order. An iPhone's keyboard has them on the screen. Right there. On. The. Screen. I can see them. I know what to press.
So, back to the topic. Black.