My current favorite: Dwight Yoakam.
Lots of good guitarwork and twangy vocals, but the music isn't overly polished with a glossy sheen like much of today's county. I'd recommend getting both his earlier hits CD "Just Looking For A Hit" and his later hits CD "Last Chance For A Thousand Years: Hits of the 90s". I'm also a big fan of the CD "Dwight Live"; heck, that might could substitute for a greatest hits album. I think the songs on "Live" are sometimes better than the studio versions since they have lots more energy. Also, there is an interesting album called "dwightyoakamacoustic.net" that is Yoakam singing and playing acoustic guitar (really shows off his voice) but the songs are not necessarilly the hits.
Other favorites of mine:
Waylon Jennings and Willie Nelson (combined and individually)
Oak Ridge Boys
(especially the Oak Ridge Boy's late 80s and early 80s stuff... though they had a nice song here and there afterward into the early 90s, the albums from that era tended to be a couple of good songs with a lot of bad filler... still they're one of my fav country bands, though).
My honorable mentions:
George Strait (but, honestly, out of his 50+ number ones, I really only like about 5 or 6 songs)
Faith Hill (just a few of her pop songs)
Dixie Chicks (just a few of their songs, though)
Charlie Daniels Band
Statler Brothers (OK, pretty much just 2 songs I like, but...)
Toby Keith (just a few of his songs)
Charlie Pride (OK, so I only know one song, but it's pretty awesome)
Well, maybe some of those honorable mentions aren't quite exactly country; but sort of, I suppose?