I bought my iMac 24" two days ago at Apple's Fresno store. I also ordered 4GB of Mushkin RAM from Newegg before driving to Fresno. Amazingly, the memory arrived the next afternoon, and I had only chosen UPS guaranteed 3-day shipping.
I decided that even if I waited for the next update, Nehalem would most likely render it "obsolete". My wife and I needed a second Mac more than I needed any foreseeable updates.
The difference between the glossy screen and the matte screen on my Core Duo 17" is striking, a difference made more clear when I had them side by side to transfer files.
Enjoy your new Mac.