P4 2.8 (800) - good choice, go 2.6 if you want to save some money and you are gonna OC
MSI 865PE NEO2 FISR - COMPLETE garbage, get a IS7/IC7 or P4P800/P4C800
512 DDR400 PC3200 - what brand? get pc3500 if you are gonna OC
ATI RADEON 9800 PRO - good choice
W.D 32G (10000rpm) - good choice