Emmylou is one of my favorite artists. I generally prefer her pre Wrecking Ball albums. She's been making them since the 70s.
For best sound, she put out a 4cd 1 dvd set not too long ago titled Songbird. It's a collection of some of her favorite tracks from throughout her career along with quite a bit of unreleased material. The sound is quite a bit better than the cds released prior to it. The dvd is not anything special and probably should have been left out.
A few of my favorite albums are:
Quarter Moon in a Ten Cent Town,
The Ballad of Sally Rose,
At The Ryman (really good live set with the Nash Ramblers, an acoustic/electric band including Sam Bush),
Cowgirl's Prayer
Spyboy
IMHO you can't go too far wrong with any of her earlier albums. Her voice started to go around Wrecking Ball and she moved away from her country/country rock roots. All I Intended To Be is a bit of a return to her earlier style.
In any case, you're on to a great artist and have a lot of really great music to discover. Enjoy!