The country/rock is pretty-well covered in the other thread. But I also like some of the Jesse Winchester and early Jesse Colin Young.
Keeping on the Jess(i/e) theme, I just picked up a Jessi Colter album this weekend from the mid to late 1970s called "I'm Jessi Colter" that not only sounds amazing, it is excellent music. (She was married to Waylon Jennings at the time but her talent is all her own.)
If you want to pick up some really nice sounding female vocals with great harmonies, good playing and good production, and DON'T LAUGH, get The Judds first two albums on vinyl.
I've found that most of the 1980s country stuff, even the digitally recorded Warner Bros stuff, sounds really good.