This is my first time building a computer and just wanted to make sure that i wont have any compatibility issues when i go to put everything together Ive been watching this forum for quite sometime and have done a fair amount of homework so i don't think I should have too many issues. I plan to use the computer for mostly gaming and holding/playing music and browsing the internet. I plan on going SLI in the future when Diablo 3 comes out so im trying to future proof my computer a little bit. If any one sees any places were I might be able to cut a few corners or could get some good improvements for cheap I would be open to suggestions.
You wont get a benefit from 8GB of ram when gaming, 4GB is plenty.
Swap the HDD for the samsung F3, its one of the fastest HDDs and isnt too much, also your current one is an IDE drive which means you need to use a PATA cable, SATA cables are far easier to manage and dont block airflow as much.
GPU - HIS H587FN1GD Radeon HD 5870 1GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card
RAM - CORSAIR DOMINATOR 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model CMD4GX3M2A1600C8
HDD - SAMSUNG Spinpoint F3 HD502HJ 500GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
Dvd - ASUS Black 24X DVD+R 8X DVD+RW 12X DVD+R DL 24X DVD-R 6X DVD-RW 12X DVD-RAM 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM 2MB Cache SATA 24X DVD Burner
PSU - CORSAIR CMPSU-650TX 650W ATX12V / EPS12V SLI Ready CrossFire Ready 80 PLUS Certified Active PFC Compatible with Core i7 Power Supply
Case - Antec Nine Hundred Two Black Steel ATX Mid Tower Computer Case
Im a little worried if the 650w PSU will be able to handle two crossfire 5870's and weather or not those 5870's will be able to fit into the 900 two midtower case. Thanks again for all your help its really helping me to do my research so I can be confident when I go to purchase.
I would suggest a HAF 922. I worked in an Antec 900 this past weekend and they're not very roomy. HAF 922 has plenty of room and great stock cooling. Shouldn't be too much more expensive, either. i think they're currently $90 on newegg.
If you're looking to crossfire 5870s in the future, maybe up to an 850 TX to give you plenty of overclocking and expansion headroom.
Another thing, you're unlikely to need to SLI/Crossfire either a 470 or a 5870 for Diablo 3. Blizzard usually does a very good job of keeping system requirements low in order to appeal to a wide audience.