go with a amd athlon xp, 2800+ or higher, amd are much cheaper and i have always recomended AMD and so would heaps of people here on Tech forums, i use a Asus A7N8x-x with my AXP but heaps of people say Asus is crap but if your not overclocking, Asus should be fine, for Athlon xp, go for a Asus a7n8x, its fast and full featured. since your going to go with a last generation video card, go with the 9800xt but since you need VIVO, make sure you get that model. the HDD's since youre getting 2 of the same, use raid 0 , it increases hdd performance alot, you could get a wd 200gb hdd with 8mb cache SATA which will boost performance slightly.
hope ive helped
Core 2 Duo E6400, DFI Infinity 975X/G, 2x 512mb DDR2 667mhz, Albatron 7900gt, WD 200gb SATA, Samsung DVD-RW, Silverstone ST-50EF 500w PSU.