If you are a gamer, a distinct disadvantage of a wireless ISP is high latency (ping). The high latency that is observed can cause problems with Internet gaming and VoIP service.
What you really need is a fast, low latency Internet provider (ISP). Depending on what types of Internet services are available in your area, a fast cable or fiber plan would be my first choice, followed by DSL and finally a satellite or cellular wireless ISP.
For online gaming low latency is very important.
Latency is the delay (ping time) in milliseconds that it takes the signal to travel to the server and back. The lower the number the better, but you'll definitely want a ping time of under 120 ms or you'll have major problems. Ideally you want less than 80 ms ping to the gaming server.
Ping time depends on distance and number of connections. Your connection may have to be routed through 15 or 20 hops (different locations) to reach the gaming server. Each server adds more delay (latency) due to the distances that the signals must travel. Try to choose a closer gaming server to lower your ping time.
That being said,
You can also experience gaming lag from a poor wireless connection between your computer and the router. Wireless connections suck for online gaming.
Wireless signals are affected by many factors including wall density, electrical interference, directional antenna range, etc. Your latency (ping) may be 30 ms and wireless interference could cause it to spike to 200 ms or more.
For serious gaming or video streaming your best bet is a direct Ethernet connection. Ethernet is unaffected by wireless interference and will give you a rock solid, stable network connection.
If it is not feasible to run Ethernet cable the next best option would be a set of powerline network adapters http://isp1.us/reviews/netgear-xavb2101-powerline-adapter/
You plug one in by your router and one in the room where you need access and connect them to the devices with standard Ethernet patch cables. The network signals are transmitted over your existing home electrical wiring which will not be affected by wireless interference. There is still overhead in the connection but it is much more stable than WiFi.
Good Luck...