One of our favorite younger groups is Lake Street Dive. They are clever writers/arrangers, great singers, great musicians and very visual.

Lake Street Dive

Another has already been mentioned by floyd (who turned us on to both of these) is Tyminski. A great case of re-inventing yourself and moving to a modern sound. Dan Tyminski was George Clooney's singing voice in Oh Brother, Where Are Thou, was in traditional bluegrass bands, played for years with Alison Krauss and Union Station and now has ended up on The Late Show with a new career with a modern sound.

Tyminski