Seriously... nothing beats a good router with the proper firmware installed for customization. Also something with an additional amplifier to extend the range. I can tell you my basement performance for streaming video improved substantially with an amplified router. Avoid the apple products. While they will be very user friendly you'll be disappointed by basement performance, price, etc.
You do not necessarily need dual band at all. 5GHz really doesn't help with range all that much because its attenuated much more easily by walls and concrete... 5Ghz tends to work well when you have highly congested 2.4Ghz... and unless you live in an apartment where you are surrounded by routers, microwaves and phones. Not really necessary but a nice to have for future-proofing... Simultaneous dual band in that case as you don't want to limit yourself to have to use 5GHz in all places and spend money on adapters.
Buffalo's High Power line of routers all are very good for range since they contain an amplifier that'll boost your range and signal quality. They are reasonably priced and all support DD-WRT
http://www.buffalotech.com/products/...access-points/
Netgear's WNDR3700 is also a very good choice.