Great country music recording

Ray Charles' Modern Sounds in Country and Western Music

Townes Van Zandt. Steve Earle, another favorite of mine, said of him, "He's the best damn songwriter around, and I'll stand on Bob Dylan's coffee table in my boots and say it!" (That's a pretty good paraphrase from memory.)
I go along with Lucinda Williams, and would add "The Flatlanders," especially their first album, "More A Legend Than A Band." Also, anything by Gram Parsons.
An interesting new one I picked up recently is Ramsay Midwood's "Shoot Out At The OK Chinese Restaurant."
Sorry, they're not mainstream, but that's why I like 'em.

All of the above suggestions are good.
I would add:
Kevin Welch
Jim Lauderdale
Jimmy Dale Gilmore
Kelly Willis
Gillian Welch

For especially good steel guitar work:
Waylon Jennings had a steel player named Ralph Mooney, he was one of the best in country music. A couple of albums really stand out, "This Time" "Honkey Tonk Heroes" "Lonsome O'nry and Mean" are my favorites, there are more.
The Flying Burrito Brothers had a really good steel guitar player named "Sneeky" Pete Kleinow. Their albums are good, especially "Gilded Palace of Sin". While we're on the Burritos, as someone mentioned above, anything by Gram Parsons is good.
I have been a big fan of country/alt country for a long time. Most of the recordings are very well done and sound great on a good system.

Yes, I am more into Alt type country.

Lucinda Williams, Roseann Cash, Kim Richy, Steve Earle, Allison Kraus are great picks from my side of the fence.

Rodney Crowell's -Fate's Right Hand is great.
The American Recording sessions of Johnny Cash are stone cold great.

Jim Reeves, Patsy Cline, Hank Williams (from no to any number), Loretta Lynn have great songs.

Decoration Day by the Drive By Truckers is a recent one I have that is a lot of fun.

Flatlanders is a wonderful pick.

Great selections by everyone really. Have Fun!!!!

Vince Gill- "High Lonesome Sound" ... For high quality modern recording
Lean Rymes(sp?) "Blue"... Outstanding modern female singing
Patsi Cline "Greatest Hits" Outstanding all time female vocals
Willy Nelson "Red Headed Stranger"... For the story of the outlaw
Neil Young "Harvest" ... For the poetry
Greatest Hits George Jones, Willy Nelson, Johnny Cash, Merle Haggard "Kings of Country, Vol I & II"... For best ever buy off a TV commercial
Doc Watson... Everything he ever recorded... For the pure joy of American music