Whilst in no way a commercial grade router, I've been very happy with my two Linksys WRT54G units (one an AP, the other a client bridge) with the DD-WRT firmware on them. Does everything I need and they never need rebooting.

Bought a couple in my previous employer and immediately put DD-WRT on them. Never rebooted them either.

Just make sure you get a hardware version capable of running the full DD-WRT. The WRT54GL will guarantee that.