I also see (in the second post!)
The Punch Brothers - This is mandolin virtuoso Chris Thilie's band. The guy is a phenomenal player.
Tim O'Brien - Another of my personal faves. I've stalked him at festivals, in fact, and got to lightly accost him in an elevator.
Great mandolin player and songwriter. His album "Cornbread Nation" is one of my favorites, and the song "Father, Forgive Me" is what a spiritual should always be. He also plays a lot with the above mentioned Darrel Scott.
To expand on Jerome's comments:
Chris Thilie's Punch Brothers were a huge part of the soundtrack for the recent movie "Inside Llewyn Davis", and Chris is also back together (most likely short lived) and touring with Nickel Creek this summer. Nickel Creek's other members are Sean Watkins (acoustic guitar) & Sara Watkins (violin). Sean was also in the group Fiction Family with Switchfoot's Jon Foreman, and Sara put out a solo album a little while back that I thought sounded great, but I'm a contemporary folk genre fan.