There are some truly great artists in the alt-country/Americana genre, my absolute favorites being Lucinda Williams and Buddy Miller. Lucinda has been putting out record since 1978 with her most famous being "Car Wheels on A Gravel Road." Her mix of country, blues, and rock along with great lyrics has made her a bit of an underground icon. Some of the guitar players in her band have been Gurf Morlix, Doug Pettibone, and Blake Mills. Check her out!
Buddy Miller first came to attention with his work with Emmylou Harris as her guitar player. Once I got into him, I realized he had a number of solo records and some with his wife Julie Miller. Not only is Buddy a fantastic guitar player, he's an amazing singer and songwriter too. He's also a part of Robert Plant's Band Of Joy. Buddy's playing is distinctive and soulful, so please check him out!