Is this a good prebuilt computer for gaming like world of warcraft?

Is it a good prebuilt - No, not really, its over done in some areas and under done in others.
Will it run WoW - Yes, wow isn't a hugely demanding game.

Are you open at all to building yourself? This way you can get a great set up for cheaper than prebuilt with better components.

For the price you would pay for the system you linked, I would recommend building yourself or if you know someone that can build for you. Yes the system would run WoW but for the kinda of cash you would spend on this system. You could build something a lot nicer that would blow WoW out the water and any other game you choose to play this year.

Yes I am open to building one i know someone who can make it for me but i do not know what parts to get to make a nice build for a buget of $1,300 if you could list the parts that you think would be alot better that would be greatly appreciated.

Becasue want to be able to run WoW on ultra and not have it completely trash my frame rate.

You can run WOW on ultra for like $600-700 depending on if you need a windows license or not.

Here's a build for your budget. This will max WoW and many more besides

PCPartPicker part list: http://pcpartpicker.com/p/AkI6
Price breakdown by merchant: http://pcpartpicker.com/p/AkI6/by_merchant/
Benchmarks: http://pcpartpicker.com/p/AkI6/benchmarks/

CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor ($189.99 @ Microcenter)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($29.99 @ Best Buy)
Motherboard: ASRock Z77 Extreme4 ATX LGA1155 Motherboard ($119.99 @ Microcenter)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory ($49.99 @ Newegg)
Storage: Crucial M4 128GB 2.5" Solid State Disk ($107.95 @ Mac Connection)
Storage: Seagate Barracuda 3TB 3.5" 7200RPM Internal Hard Drive ($124.99 @ NCIX US)
Video Card: XFX Radeon HD 7970 GHz Edition 3GB Video Card ($424.99 @ NCIX US)
Case: Cooler Master HAF XB (Black) ATX Desktop Case ($94.99 @ Microcenter)
Power Supply: XFX 650W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply ($104.99 @ Newegg)
Optical Drive: Samsung SN-208DB/BEBE DVD/CD Writer ($26.98 @ Newegg)
Total: $1274.85
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-01-29 17:22 EST-0500)