x86_64 with at least two NICs, Intel preferred (at least 4 if your area has gigabit service on the way), AES-NI, dual-core or more; managed switch; discrete AP(s) (either purpose built or decent, current all-in-one devices configured as "dumb APs"). That's the only "clear winner" in my opinion, but not what many people have in mind when they think "router". (There are devices that meet this criteria in the 10 W class that are similar in size or smaller than all-in-one routers.)
With gigabit symmetric available in the home at US$70 a month, enterprise-level bandwidth basically requires enterprise-level equipment. There are plenty of additional reasons to select a device with RAM in the GB and the ability to run a fault-tolerant file system beyond just bandwidth.
One person's opinion who I respect and some good follow on at