http://www.newegg.com/Product/ComboB...t=Combo.827606 - Good value (the FX8120 is so close to the FX8150 for the price difference, as well as they both Overclock to around 4.6Ghz to 5.0Ghz) You will definatly want to swap out the 5900RPM Hard Drive for either a 7200RPM or an SSD for better loading times. 2GB is way overkill if you are just gaming anyways. A great SSD is the Crucial M4 or Corsair Force Series 3. (The Intel SSD's are very reliable though, but a bit slower)
I'd also recommend picking up an aftermarket CPU cooler for this style of build, as the AMD FX CPU's run warm. Even if you aren't overclocking it's nice to have a bit more thermal headroom. Aftermarket coolers are also a great deal quieter than the stock AMD cooler.

http://www.newegg.com/Product/ComboB...t=Combo.791304 - Although a bit above your price range this is a nice choice.
You can't go wrong with the i7 2600k. The AMD 6970 series video cards are nice. A 60GB SSD is kinda small even for gaming, you'd want one a bit bigger (around 120GB at least) Gigabyte motherboards are decent, but if you could switch it for an ASUS board, it'd be better.

http://www.newegg.com/Product/ComboB...t=Combo.827614 - A bit overpriced, not a good choice

For video card selection - Single powerful graphics card is good for MMO (unless you are playing WOW, then you just need a Comodore 64 to play max at 60FPS)

First Person Shooters benefit from Crossfire or SLI (Multiple Graphics Cards) setups to get insane FPS to gain an
advantage on speed.