But if you're playiing online, the slow link is not your router. Even getting "54 Mbps" (which you're not, due to overhead) is faster than 1.5Mbps DSL, 6-10 Mbps cable, and even the 15Mbps FIOS.
Home networks are always faster than your internet connection (unless you live in Korea). The issues with wireless are interference from other things (phones, microwaves, etc.). The 360 wireless adapter can do 802.11a, which is discreet from these devices, but you need a router that can do 'a'.