Don't use wireless for console gaming
I was reflecting and remembered that one of the supposed cons of the Xbox 360 is that it doesn't have wireless built in. I replied saying that wireless isn't really a pro for a console. Wireless is extremely inferior to wired when it comes to network reliability and stability.
There are several problems with wireless. The faster the speed of the wireless, the smaller the range gets. Even then, the available speeds are still slower than standard CAT5e cable can do. If you use encryption (which you should) then your throughput speed gets reduced, even on 64bit encryption. Interference is also a problem as well, whether it is tangible or not.
This got me to thinking about lag with online games. I bet some of it is caused by wireless connections since they can be so poor. Although there are dozens of reasons your connection may have problems, if wireless gets popular for consoles (no thanks to Sony or Nintendo...give the REV AN ETH PORT!), then the problem may become more apparent when playing against wireless users.
For smaller games (DS, PSP) or internet browsing, wireless is fine. But you wouldn't want to do large data transfer on it regularly. With these next-gen games, there is a lot of information to pass when playing a multiplayer game. Wireless just isn't the right venue yet.
Another problem is that built-in network cards (wireless ones for the sake of this post) are generally not upgradeable. Say technology can make 1000Mbps somehow a reality for wireless. If your card is built in, you can't upgrade. You have to leave it in and get an external one anyway!
Okay, so the first thing I will hear is "not everyone has their x console by their computer". Before I go on, that means that you might be using your computer as the router via Internet Connection Sharing. That's another inefficient way to go about home networking (yes, even on Linux). Buy a router designed for the purpose. It works a hell of a lot better. Then, wire your house. If you have an apartment, then just don't drill any holes. Cat5 cable isn't that expensive (Cat6 on the other hand...). Most of the time, an ethernet jack is already built into your computer!
People ask me to network their houses all the time. I always tell them to avoid wireless if possible. If they want wireless, then get a wireless router, but hardwire the devices that don't move all the time. I will admit that I query on the exact environment before I come to that conclusion (if they don't game, and just do email and browsing...then wireless is fine). But for the most part, I just cannot support wireless for everything. Desktops and consoles being at the top of the NO-WIRELESS list.