Well the backbone of you system is the mobo. Make sur to buy one that do not have sound, video and lan as you will probably buy these components. Also since you want a high end look for a mobo that takes 533 Mhz memory chips. I would look for the make ASUS and suggest you this one:
(I know you AMD fans have other suggestions, it's OK)
With this motherboard, you can attach a 1 Gig of 533 Mhz RAM (get the lowest cas latency type for better speed). If you want speed from you hard disks get 10,000 rpm SATA hard disks (Western Digital makes some) and configure them in RAID 0 [[SATA hard disks can deliver up to 150 Gb/s of transfer, while ATA 133/100 ; the number indicates their Gb transfer rate (max). In RAID 0 two WD SATA 10k rpm deliver sky rocket speed in RAID 0 configuration.
Most new motherboards have SATA and IDE connections and sometimes by default in the mobo BIOS, SATA is not enabled.
Concerning the video card, get what is best for your money. Look for 8x AGP high memory brand name cards, and check the company website for support! prior to buying to check there on-line service.
For the sound card, if you know what games you are going to play check what minimum requirement they have for the sound card. A cheaper sound card won't generate certain sounds!