Some of my vinyl is from my youth (mainly have cassettes) and others I have filled in over time. I only get stuff I am sure to be able to put in and enjoy as an album...so less and less is making the cut these days.
To give a general sense of it, I have every Sonic Youth, Dinosaur Jr, Pixies, and Fugazi album on vinyl. I also have an assortment of Stereolab, My Bloody Valentine, Jesus and Marychain, and Black Sabbath.
More recent stuff includes Broadcast (Ha Ha Sound), Deerhunter (all), Atlas Sound, War on Drugs, and various Captured Tracks releases.
Great finds in recent years include Nancy Sinatra (Boots) and Frankie Laine (Hell Bent on Leather)
You know an album is a keeper when you have it in more than one physical format.