Several years ago I got sick of going through the cheap sub-$200 routers.
Being the Network System Admin for several local ISPs I wanted the same performance and the big guys, but, didn't want to spend $$$$$$ doing it.
In my search I found the answer: IPCOP
http://sourceforge.net/apps/trac/ipcop/wiki
Easy to install, easy to admin, and just sits there and WORKS, 24/7.
I got an old dual processor P3 450, put 128 Megs in it, an old ISA Video card, 2 network cards, and loaded it up. (you only need a monitor to install it)
BTW, you can also put a 3rd card in it, use a wireless card and have a wireless router also!
If you are looking for a professional grade router/firewall on the cheap that will never bottle-neck your game play, this is a very good system!
The only maintenance I do...... every 6 months or so I unplug it and drag it out to the shop to blow it out with my air compressor.