One thing that I often find is that I have to hear a whole album before I decide if I like a group, just as with other types of music. Some of the best songs never see much (if any) air play.
Must haves from the last few years:
The Cowboy-Junkies as mentioned
Alison Krauss + Union Station LIVE (especially if you liked O Brother, Where Art Thou ) (bluegrass)(great songs, great sound)
Two important questions:
1.) Do you like men's voices, women's voices, both, or...