The Intel Sandy Bridge processors will be released mid-January 2011. It could be worth waiting for those, if only in order to see how it would affect the prices of current Intel and AMD processors.
Normally, I would also say get an SSD, like an 80Gb one, (either Intel or OCZ) to use as a boot + main programs drive. They are unbelievable doubleplus good. It's probably the biggest upgrade in perceived performance someone can do in a modern computer. This is especially relevant if someone uses many programs and fastly switches between them (ie, Photoshop and 3Ds Max) in a short amount of time although less relevant if someone just wants to run single programs (ie, a game) for long periods of time.
I also just suggest to everyone the Lian Li
PC-A05N case. Basically it does a clever trick with the PSU which results in the case being as tall as an ATX motherboard. Geometrically speaking, its probably the smallest case someone can get for an ATX based configuration and I don't see why anyone would ever choose anything bigger than that. I like the looks too.