Personally id go intel, with say a 2.26B p4 as they seem to be a good combination of speed/price, or as good as you can get with a p4 that is

The 133mhz bus makes quite a difference so i wouldnt settle for a 100mhz version.
As for motherboard id go for the...
Abit IT7-MAX2 using the 845E, chipset.

Should be plenty fast enough and offer pretty much every feature you could want.
Graphics wise its gonna have to be either a GF4 Ti. Your choice on which 1 as they are obviously the same thing but just clocked differently

or wait till next month and grab a Radeon 9700.
For sound, i have an Audigy Platinum as i thought i would have the odd go at doing music and ive been very pleased with it. Its had far more use than i initially thought it would have

RAM wise, 512mb is what i would recommend or 1024mb if your feeling adventurous

As far as HDDs go, alecstaar has mentioned the 1 i would get, the 8MB buffer WD drive, but you pay more obviously for that buffer

Anyway thats what i would recommend, i personally would get a RDRAM system but i find it harder to recommend them to anyone as each day goes by