You need to weigh the good and the bad. The white iMacs have a better screen, but the AL iMacs are better in every other way.
Personally, I'm waiting. I think the AL are still too new, there are a lot of bugs to be worked out. I'll wait until they have a better screen too. And I don't want to buy a white iMac, since they really are limited at 3GB RAM for the kind of work I want to do on them.
In fact, I thought you had the right idea - mini + monitor... except you don't already have a monitor, which makes the deal less great financially (FWIW, the Dell monitors give you the best bang for the buck).
If you really need a computer, I'd go with the AL iMac, just be prepared to return it in case the screen is defective (a lot of them are).