Build it yourself - I have no idea what brand half of those listed parts are, and as a result I have no idea if they're reliable or any good.
You're going to struggle getting a system that can play newer games AND WoW on that budget - WoW really doesn't need a very powerful graphics system, but newer games do, and that's where the money goes.
At Christmas, I built a dedicated WoW box designed to run everything maxed out at 1920x1080 (my 50" plasma TV). Here's the spec:
Phenom II X3 550 Black Edition
4GB Patriot Sector 5 Viper II 133MHz CAS7 DDR3 RAM
Asus M4A785TD-M Evo AMD 785G Motherboard
Sapphire Radeon 5770 graphics card
500GB Samsung SpinPoint F3 hard drive
Sony 24x DVD Rewriter
Corsair CX400 PSU
Antec Mini P180 case
all in that was £500. Now given that everything's a good deal more expensive here in the UK, see how much that translates in US$
Note that I could've saved a fair few bucks too by getting a cheaper case (and I wish I did - Micro ATX my ass!)
It's easy - you buy the bits and stick them together because they'll only go in one way.
I suggest building your own because most places I know that sell pre-built systems will cut corners somewhere to keep the costs down, and it's usually with the power supply. You never want to skimp on a power supply.
Although I'm from the UK, a lot of US residents on these forums don't have very positive things to say about CyberpowerPC and iBUYPOWER systems. I'd suggest looking at a local shop and talking to them and see what they cam come up with.
At the very least you could give a specific component list (that we'd help you with here) and they'd build it for you - best of both worlds if you don't want to get your hands dirty.
And seriously, get your hands dirty because it's easy, lots of fun and as your knowledge grows you can diagnose, fix and upgrade your systems confidently.
A true budget gaming PC is a 2GHz dual core, 1GB of RAM, 80Gb HDD, and a damned GTX 480 or 5970!
The only thing that I truly disagree with in your current build is the GTX 260. If budget is truly a concern, why go for a old yet still expensive card?
A ATi 5770 is $50 cheaper and has the same performance.
I also recommend the absolute cheapest DDR3 kit you can buy. Cas9 1066MHz will make no real difference, while costing a hell of a lot less.
Good dual core, decent HDD, good power supply.
I say go with it (other than replacing the graphics card).
Hope you enjoy having a hand built rig. Hope you have good lighting and stable hands (which I had neither of). Also, best of luck that you finish the build off, move the case, and don't hear a single screw moving around.
ASUS P7H55-M PRO LGA 1156 Intel H55 HDMI Micro ATX Intel Motherboard
Seagate Barracuda 7200.12 ST3500418AS 500GB 7200 RPM 16MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
Plus a DVD burner and Windows 7...for a grand total of us over 800 including a case.
What do you think?
I'd not bother with the GTX260 - it's old, loud, hot and outperformed by cheaper and similar-priced cards. Either go for a 5770 1GB for similar performance and a few bucks cheaper or 5830 1GB for a lot more performance for a few bucks more.
Also, you can save a few bucks going the AMD route - look at an Athlon II X4 with an AM3 motherboard. It's about the same price as the i3 but you get a quad core, not a dual core, and for the single graphics card you're running you won't see a performance difference.
I also wouldn't bother with Corsair RAM - it's a bit expensive for what it is. Look at some Geil or Patriot instead, and you can get a CAS9 kit too for a few extra bucks saved (and then probably just tighten the timings to CAS8 when you build the system anyway).
The PSU is great and will last you a while, and will run a second Radeon 5770 in Crossfire when you want to upgrade your graphics performance later on.
Personally I don't like Seagate drives - every drive that's ever died on my has always been a Seagate. My preference is the Samsung SpinPoint F3 - faster, quieter and cooler, and the 500GB version is cheaper than the Seagate too.
Was looking at kits on Newegg and found a Hexa core kit for only $650. It does not include a HDD, heatsink, or video card but it is a Hexa core system. I was just reading in MaximumPC about the AMD Hexa and it was talking about how it will overclock a couple of the cores if the programs that are running are only using one or two cores and not all six. It is a way of improving performance of programs that don't take advantage of multi-threading.
Also, Asus has a PCIeX4 card that has both USB 3 and SATA 3 on it for only $30. Just remember it is an X4 so you would have to use one of the X16 slots to use it because the motherboard in that kit only has X1 and X16 slots.