the rt-n16 is also excellent which is the router I have.
http://www.amazon.co.uk/ASUS-RT-N16-...eywords=rt-n16
The difference from the n66u is mainly the lack of dual band wireless. I would say this is a very good 2nd choice if th en66u is too pricy for you.
Both routers will run tomato which is excellent firmware, the traffic logging on it is the best I have seen on any firmware/router. Also various advanced features as well.