well, linksys WRT54G routers very from good to suck (based on version, newer version actually have less memory. I think the 'best' wersion of that model is 3, provided you know how to change the firmware)
routers are tough, since usually the information that matters is hidden (so you can't compare it to others, its like a industry wide ban on giving cust the "not-needed" info especially since it can be missleading.) Gameing or other high end routers will brag about their stats (of course, because they are good but cost a lot) but most standard routers won't tell you anything. Linksys is generally very solid, and its easy to put on more efficiant firmware if the defaults don't suit you for whatever reason.
A big factor is what you are also doing. It sounds like you're doing a lot of gaming, which often needs something that minimizes latency. Gaming from 360s usually have high MTU, which means something with enough ram for all the games at the same time. It becomes rough if the PC is doing something like P2P traffic that uses a bunch of connections at the same time. The traffic from those are usually small quick packets. That requires many caculations per second. If the PC isn't doing anything most of the time, a cheaper router would probebly be fine.
Very few networks can support the need for wireless N right now. Wireless G (max of 54 Mbps) is usually enough. The major part is when it comes to file sharing, if you do a lot of file sharing (PS3 can do it, I'm not sure about the 360. Obviously the PC can do it) then wireless N might be a good move. The reason is because it doesn't rely on your internet connection (if you have a 3 mb connection, you have a max of 3 mb for gaming and downloading, but you can still trade files between your computers at full network speed when inside your own home) the consoles can't support N, they would run as G anyway.
I personally use wireless N, because we have wireless N laptops and I have a "terastation" external hard drive server that supports 1gbps ethernet connection, and we do a lot of file sharing (passing around videos, 3D models, programming apps and you name it) so its worth it for me. But not for most
*added, looks like psychoak was 2 min faster