Was only able to do the northern circuit in the month I was there, but it was fantastic!

Did a community based trek with TESFA in the Wolo Highlands (between Lalibela and Bahir Dar) that was extraordinary. Many locals had never heard of the USA. Kind of nice.

http://www.community-tourism-ethiopia.com/index.htm

Lalibela is great itself, but I also really enjoyed Tigray and the churches north of Wukro.