What's a good wireless adapter for this motherboard?

For gaming you much better off getting a powerline adapter over wifi (of course hardwired Ethernet is better).
No matter how good of an adapter you get you will always have more latency/higher pings with wifi, that is just the physics of wireless.
For gaming the latency/ping is much more a factor then the mbps which is more of a capacity then a speed, you need to send a little bit of data very fast, not a lot of data in one trip; hence you need the sports car not the 8ft bed truck.

I would recommend this: http://www.amazon.com/TP-LINK-TL-PA4010KIT-Powerline-Adapter-Starter/dp/B00AWRUICG/ref=sr_1_1?ie=UTF8&qid=1425484186&sr=8-1&keywords=tp-link+powerline
 


I don't know how to set up a TP LINK D: