Oh no! Don't show him the color configurator! It's a curse in disguise. (Seriously, that thing alone delayed my order by some two weeks or so.)

I myself have a Brompton M6L (you can see it here: http://www.bikeforums.net/showthread...-have-a-folder!)

As you can tell by the name and the pic I went for one without a rack. And as you I first thought about having a rack, but decided against it. My reasons were that I don't use the rear rack on the other bike i have, it adds weight and costs money. Plus if you put something on the rack you can't park the bike (in the Brompton way).
The upside with a rear rack is that you can get more stuff on your bike, it's easier and more stable to roll when folded. This is true even if you get the Eazy wheels on a L version. But since I don't plan to roll it that much rathar than carry it on and of busses it didn't matter to me. Plus, if you want you can always retrofit one should you need it (goes for the L rear fender as well). If I were to get a rear rack I would look for possibilities to mount a kickstand on the bike.

Color is a matter of taste, we can't help you there.

I chose the folding basket for me because I will mostly use it for shopping. A good thing about all bags though is that the steel frame which attaches the bags to the bike is seperable so you can use it and strap on whatever you like on it.