It is unlikely that you will notice any difference between your wired connection and a wireless connection, unless your signal is unstable due to large amounts of interference (in which case the newly announced Wireless N adapter should help significantly).
Are your internet speeds faster than 54Mbps?
Well, since you think it is unlikely that I would notice the difference, I would deposite you would be surprised to see the difference in 10-20ms in competitive online play in an FPS.
And most g/b routers don't reach their 54Mbps peaks, but that isn't the point. As I said, latency--not thoroughput. I would take a 10Mbit connection with extremely low latency than a 1000Mbit one with additional latency + extra potential for interference.
Why? Do you also recommend people dump their LCD TVs?
I would NOT recommend a high latency display. Just ask Homer and some of the others here who have had to endure high-latency displays in competitive online games: They. Suck.
So if someone has a choice between (a) lower latency, cheaper solution aka a cable or (b) going for convenience that has higher latency and potential for interference aka wireless for the sake of some setup convenience, from a *gaming experience* POV this is a no brainer.
But go ahead, continue selling wireless as a selling point for online competitive gaming! You got your sales bullet point and yet bash something usefull (like party and cross game chat).
Wireless has its uses (and some customers have no choice), but anyone serious about online gaming, when given a choice, isn't going to spend more to get a worse experience.
This is no different from suggesting a freaking 1080p display with high latency over a 720p display with low latency because it has a bullet point. There may be other factors, but your primary criteria is playing 720p games competively online it is a *no brainer*.
So while I have no recommendation for someone dumping a high latency display they own, if someone is buying *now* I think the choice is obvious with these criteria.
I don't recommend wireless to anyone looking to do competitive online gaming. Why choose yet another layer of latency and additional potential interference when there is a cheap, lower latency connection less prone to interference if performance and experience is your criteria?