Netgear WNDR3700 tops the list but it is expensive.
For DD WRT, try to avoid Linksys Dual Band 11n routers because they are hit or miss - hence all the scrapped models. Configure DD-WRT QoS with the QoS generator application - change language from Polish to english.
11g
WL-520GU (affordable, great wireless performance, removable RP-SMA antenna, USB, also runs tomato)
WRT54GL (more expensive but fewer features)
2.4Ghz 11n
RT-N16 (128MB RAM, 32MB Flash, 5Ghz chipset but 5Ghz permantently disabled, Great 2.4Ghz performance)
http://www.smallnetbuilder.com/wireless/wireless-reviews/31058-asus-rt-n16-gigabit-n-router-reviewed?showall=&start=4
RT-N13U (Excellent Wireless Performance and great range)
http://www.smallnetbuilder.com/component/option,com_wireless/Itemid,200
Dual Band 11n
WRT320N (Selectable Dual Band because of single radio)
Used WRT610N or WRT600N can work well in DD-WRT will simulatenous freq functionality (check Hardware versions)