(Not folk but...) well one of my all time faves is Paul Desmond's "Take 5" , which is in 5/4 time.

Something a little more current that I really like is Sting's "Love Is Stronger Than Justice" off of the "10 Summoners Tales" album. The verses are in 7/8 time, and the choruses are in 4/4. 7/8 is a very neat groove.