best ram will be Corsair Twin X (i forgot which number PC xxxx ?)
best boards, look to Asus, MSI, Gigabyte and their 875 chipset based products.
best video card Radeon 9800 pro, not the AIW, just plain 9800 pro.
best sound card Creative Labs Audigy 2 Platinum. a lot of the boards come with audio, but its not very good, just kinda basic.
Hard Drive, i don know, but i would guess either Maxtor or Western Digital Serial ATA drives (like a Raptor), although beware, peopel are apparently having problems with their raptors, i personally like Maxtor the best.
the board should come with an integrated gigabit LAN which actually really nice, so you dont have to worry about networking.