I feel like this thread was made for me to post in.
Basically, the issue with Wilco is that depending on what album you buy, you are getting a completely different band. The only real constant you are going to find is Jeff Tweedy.
So, in order.
If you are into really simple slow country jams with a bit of an Indie Twinge, get AM. It's a spectacular album, not as deep as their later stuff, but the one you are most likely to put on in the car while driving. It's also the only album where anyone BUT Tweedy sings. There's a track called "It's Just That Simple" where the bassist, John Stirrat, takes lead vocals. Other Stand Out Tracks are "Blue Eyed Soul" and "Passenger Side"
After that, you get Being There which I honestly think might be their best album, or at least the best starting point. It's almost an epic album, in some ways. There's two discs to it, and they complement each other beautifully. The first disc is for the most part way faster, more power poppy almost. It's not bad, but the second disc is the best part. Really slow, mournful, songs, with really deeply depressed lyrics. If you take the first song off disc one "Missunderstood" and add it to the second disc, you get a collection of some of the best songs of their carreer. Other High points include "Sunken Treasure" "Outtasite(Outta Mind)" and "Outta Mind (Outta Sight)"
Summerteeth is, in my opinion at least, their weakest album, but it's also the easiest to listen to. It's really just a straight up indie-pop album. It's by no means a bad album, and actually has some of the best lyrics Tweedy has ever written. The problem I have with the album is overproduction. There are just too many redundant sounds added on top of the music, which ruins the effect. There are still great songs, just not as many. "Via Chicago" and "She's a Jar" stand Out.
Yankee Hotel Foxtrot is an just 100% indie rock. Guitar Jams, random sounds, static, noise, amazing percussion, and brilliant songwriting. Tweedy's voice is at it's best, the whole album flows together perfectly... there really isn't anything wrong with it. But again, it is really easy to just NOT LIKE IT at first, because it's an icredibly dense, complicated album. Best songs are "I am Trying to Break Your Heart" "Jesus Etc" "I'm The Man Who Loves You" and basically all of them. If you can handle it.
A Ghost is Born is really closest to a sort of Indie Rock Neil Young. The guitar parts on all the songs have been drawn out into elaborate jams, sometimes as much as 10 minutes long. The lyrics are more nonsensical, but they are clearly secondary in importance to the music in this particular case. Again, it's not the most accessible of their albums, but if you are already into good music, you will start tapping your toes and singing along pretty fast. "Spiders(Kidsmoke) and "Hummingbird" are the essential tracks.
If you are a fan of folk music, Wilco did 2 albums with Billy Bragg, covering Woodie Guthrie songs. Their much more country, and you aren't getting the full Wilco experience because it's a different lyricist, but there are amazing songs on both of the albums. Great old timey feel, easy to pick up and get into. "Another Man's Done Gone" "California Stars" and "Remember the Mountain Bed" are the essential tracks. "Bed" is actually one of the best songs Wilco has ever recorded.