Most of my suggestions have already been mentioned, but I'll give 'em to ya anyway: Trampled, Yonder, O.C.M.S., Big Smith, Hillbenders, Infamous Stringdusters, Mandolin Orange, Hot Buttered Rum, Punch Bros, Railroad Earth, Salmon, Sam Bush, Bela Fleck (with or without the Tones), Iron Horse, Devil Makes Three, Carolina Chocolate Drops, Steep Canyon Rangers, Split Lip Rayfield, Crooked Still, Bill Monroe, John Hartford. That should be enough to get ya started. If I could only suggest a few: Trampled, Yonder, Crooked Still, O.C.M.S., Big Smith, and Hot Buttered Rum.