My favorite bluegrass bands:

Dan Paisley and the Southern Grass
This is very traditional bluegrass. Danny Paisley is a vocal gymnast and every time I see them Dan breaks a string.

King Wilkie
This a band made up of guys in their 20's (ancient right?) They have a great band chemistry, and are also great musicians.

Del McCoury
A family band with soaring instramentals, high lonesome vocals, and unusual chord progressions. plus Jason carter is my absolute favorite fiddle player.

Hazel Dickens
She is my favorite female singer, and one of the first great bluegrass singers.