I have set up about ~15 Buffalo WHR-HP-G54, 5 in a mesh network at my old workplace, 3 for WiFi client bridges and the rest as standalone routers for home, family and friends, all running DD-WRT.
It is not the most feature-packed router, but it's cheap and reliable and works very well with DD-WRT. All the networks I've done with them are effectively fire-and-forget. Never goes down or requires restarts, and the coverage is quite good for 802.11g when you boost the transmitter power (Default is 70mW, DD-WRT lets you boost it to 254, although I've only tried it with 100mW, since that is the highest radio transmitter strength allowed in Denmark without a special permit).
Buffalo actually ended up entering a partnership with DD-WRT, so WHR-HP-G54DD actually ships with DD-WRT installed, but I've never had one of those.