The graphic card in that computer is a 9600 GSO, not a 9600 GT. It does make a difference. Depending what the screen resolution of your monitor and which graphic card it is (there's many variations of the 9600 GSO) it could go from decent to barely adequate in full size raids. You can find a system at a better price that would perform better. This one from www.newegg.ca has a 9800GT, a faster processor and is cheaper. If you shop around you can probably find better. http://www.newegg.ca/Product/Product.aspx?Item=N82E1688...
I found the City of Dalaran to be the best test for FPS @ night during peak hours. My FPS with my old comp was 15fps average in town...strange thing is when I go into the bank it would go to 30fps. Most other places 30 to 40fps.
I built this comp for WoW & Diablo3, maybe even Starcraft2, it has the GeForce 9800GT factory OC'ed, now I get 60FPS in the bank & 40 to 60FPS out side in the street on High Quality second to Ultra.
CPU: AMD Phenom II X2 550 BE [3.1 GHz with 4 cores active]
MoBo: GIGABYTE GA-MA790XT-UD4P AM3 DDR3 AMD 790X ATX
Mem: OCZ OCZ3P13334GK 4gb kit (2gb x 2) 1333mhz 7-7-7-20 240-pin DDR3
PSU: OCZ ModXStream Pro OCZ700MXSP 700W ATX12V V2.2
VC: MSI N9800GT-T2D512-OC V2 GeForce 9800 GT 512MB 256-bit GDDR3
HD: Western Digital Caviar Black WD5001AALS 500GB 7200 RPM 32MB OEM
DVDROM: Sony Optiarc Black 24X Rewritable Drive - OEM
CASE: Antec 900
Monitor: Hyundai L90D+ 19"
OS: Windows XP Pro 32
If you want a pre-built, then dirtmountain's system is much better than the one from Best Buy, but see below, for why I wouldn't buy it. If you choose to build one yourself, Jim's build is reasonable too; I won't pick nits over it, but you may not have his luck on unlocking additional cores on the 550BE, and/or they may not be stable, so don't count on that. In your place, if budget allows, I'd get a 720BE or a X4 9xx.
I do see three potential issues with the CyberPower PC. First, the PSU is an old, inefficient design and may be utter garbage; note the voltage switch on it. Considering that a quality 450W PSU would power that rig, the "700W" one in it is undoubtedly overrated. Noting that the case is Xion, the PSU probably is this one, reviewed at jonnyguru: http://www.jonnyguru.com/modules.php?name=NDReviews&op=.... Yup, it's crap.
Issue #2 is the non-expandable micro-ATX board in it; all RAM slots are filled, and future SLI or Crossfire will not be possible.
Issue #3 is minor in comparison, but the cooling in that case is not good, with only an 80mm fan in the rear. This is not a system with any serious overclocking potential. It also has the stock Intel cooler on it.
VC: MSI N9800GT-T2D512-OC V2 GeForce 9800 GT 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Supported Video Card - Retail OC Edition overclocked to 660Mhz $109.99 This was Not my first choice for a VC but the Price was right [$59.99]...I can get a new ATI in 2 years.
My first choice when released was the AMD PII X4 955 $259.99, howver the PII X2 550 for $99.99 for RPG gaming & surfing works great
WoW supports 3 cores so the PII X3 720 is perfect.