I'd pick a router that's
DD-WRT compatible, so if you wanted you could replace the firmware. Many older Belkins are cheaper and compatible, including c.£20 802.11g models, unless you
must have 802.11n
It's probably not necessary (and not a little scary), but it's nice to have the
option as one extremely useful feature it has is to boost the signal strength - which can widen the coverage significantly, which can be an issue depending how many walls it has to go through. In addition to making sure your signal is stronger than the neighbours (heh) it has a scanning feature so you can avoid using conflicting channels.
Generally 802.11n is a waste of money unless you need to transfer very large amounts of data between devices inside the home, or have a lot of devices. 802.11g's top speed of 54Mbps exceeds most broadband speeds, so it won't be any slower for external access and the corresponding wireless cards/dongles you'll need are cheaper, too.