pick up a Linksys WRT54G on Craig's list, try to get a version 2, 3, or 4, not 1 or 5. Then install third party firmware, currently I run tomato (http://www.polarcloud.com/tomato), but lots of people like DD-WRT (http://www.dd-wrt.com/dd-wrtv3/). These firmwares are more stable and control able, you can easily OC your broadcast by 30-40%, just need to make sure you keep it cool
Even if you stick with the Linksys stock firmware, the WRT54G is a classic wireless router, can't go wrong for the money.
Cheers,
Josh
PS: Invest in a good modem, often times when the modem goes down it will freeze up the router, also most noise/interference will be generated in the modem, it can also act as a bottle neck if you have better than 10MB/s service.