I am a big fan of Scott Miller & the Commonwealth - start with 'Thus Always To Tyrants.'
I would also recommend 'Hollywood Town Hall' by the Jayhawks and 'Smile' by the Jayhawks though it's a bit experimental but contains the song 'I'm Gonna Make You Love Me' which is a classic, as well as 'What Led Me To This Town.'
The Volebeats: 'Up North' and 'Country Favorites;
Thad Cockrell - 'Warmth & Beauty' (GREAT voice - I'd listen to him sing a summons...)
Thad Cockrell & Caitlin Cary - Begonias
Caitlin Cary solo material
any album by Chris Knight
Cross Canadian Ragweed
Almost Blue by Elvis Costello - it's brilliant
Freedy Johnston (not so country but a great indepent singer-songwriter)
The Honeydogs
Kathleen Edwards
Kim Richey
Lone Justice (features Maria Mckee the High Priestess of Cowpunk)
Maria McKee - any solo material
Mike Ness - Cheating at Solitaire
Old Crow Medicine Chow - old-timey bluegrass
Reckless Kelly
Robbie Fulks
Robert Plant & Alison Krauss - Raising Sand (one of the best albums of 2007)
Ryan Adams (especially his stuff with the Cardinals) the guy may be a hot mess but he knows his way around an alt-country tune
Slaid Cleaves (great singer-songwriter folkie)
STEVE EARLE STEVE EARLE STEVE EARLE
Tift Merritt - great alt-country chanteuse
Hope this helps and if nothing else it will be fun to check these out!