For Gigabit LAN and single band, WRT310N (supports DD-WRT). It costs about $130. The WRT160N is ok (100Mbps LAN/WAN), but no DD-WRT. Dual Band (not simultaneous) Apple Airport Extreme. Simultaneous - WRT610N but it apparently is not great for the price - poor connection issues.
I have a DIR-655. I was getting the same issues as you - connection drop every 3 hours for 20 minutes or so. I really only use 802.11g, but I set the 655 to 802.11n/g mixed mode, enabled Auto Scan Channel (Very important for some reason) and used WPA2 AES encyption - but WPA1 AES is still stable too. I live in a condo where the 2.4Ghz is very crowded, after I enabled auto channel scan it never dropped since. In netstumbler channel 1 had no traffic but made the router's WiFi unstable when it was manually set to 1. When set to auto scan it avoids 1 (even though there is plenty of traffic on everything but 1) but it works solid now.
I used to hate the 655 (thought it was defective), now I love it. FW is 1.21
Unfortunately for you, the only good 802.11n router for under $80 is the Dlink DIR-625.
Please try these settings on the 655 before giving up on it. It is really a good router because it uses an Atheros Radio and has the Ubicom CPU (great QoS). Linksys WRT350N, 300N, 150N and 600N have all been discontinued or redesigned because they were plagued with very unreliable wireless problems.