Build it yourself, but go with a different hard drive, Seagate is a good brand, but go with a 7200.8 or 7200.9. And get a SATA drive as well. The speed difference is noticeable and will certainly help you with load times for the games. The page is not in English, but tech talk is universal, check out the differences between the speeds of the 7200.7 and 7200.9 is evident:
http://www.sumanet.cz/modules.php?na...article&sid=71
As for mother board, ASUS is a great brand, Gigabyte and MSI as well. Personally I love ASUS, but I have knowledgably friends who swear by there MSI boards. I just built 2 systems based off of the ASUS A8N-VM board. It’s a good board with enough options. 1 PCI Express x16, 2 SATA, 10/100 LAN (not gigabit), on board video and audio, I would recommend disabling the on board video since you will have a real nice video card in it. Check it out it’s a good price.
http://www.newegg.com/Product/Produc...82E16813131571