Newegg offers the refurbished Asus 802.11n Wireless Dual Band Gigabit Router, model no. RT-N66R, for $44.99 with free shipping. That's $5 under our August mention and tied as the lowest total price we've seen for a refurb. (It's also $55 under the best we could find for a new one today.) This router features data transfer rates of up to 900Mbps, USB, four LAN ports, and DD-WRT open source support.
A 90-day warranty applies, although it is unclear who backs it.