check out newegg.com
AMD Athlon XP 1600 and Epox8kha+ motherboard around $214
Hard Drive- Maxtor 7200rpm 40 Gb around $90
Sound Card- Sound blaster Audigy around $62
Case- Enermax, FS-710B. BLACK, 10-Bay, Enermax 330W P-4 PS, Server Tower Case $99 (you may not need that big of a case so check out there other options for cases.
Video card-ATI RADEON 8500 LE 64MB DDR - OEM/White Box - around $179
check out crucial.com for memory 256Mb pc2100 DDR around $151
Total $795
ways to cut cost....
get a cheaper video card although in my oppion ATI is the best right now you can get a Gforce2 anywhere from $50-$300, if you dont want the Radeon 8500 then go with a Gforce 2 card, The 8500 is ATI's only good card.
get a cheaper case, but if you ask around the forums and see what people are reccomending, everyone is going to tell you to stay with a good case and espically a good power supply, i wouldnt get a power supply under 300 Watts. Its much easier to work on a computer and install everything with a good case.
i would stick with the XP 1600 its the best performance for the price, unless you want to go faster in which case i wouldnt get anything faster than the 1800+
the Epox 8kha+ is a great board, I have it myself and have put it in systems ive built there are a lot of anandtech people with this board as well so finding help isnt hard. Another board to consider is the Abit KR7A. here is a link to Anandtech's review of some 266A boards including those 2.
VIA KT266A motherboard review
hope this helps
good luck
Edit........ i forgot the EPOX board has onboard sound and i think its pretty good so you may be able to get away without a soundcard if your motherboard supports it.