Great thread idea. I often take a while to get into an album so I'll have plenty to list. These are the main ones that came to my head:
Fugazi - 13 Songs
One of the first true "indie" albums I ever got into. 'Waiting Room' was love at first listen but it took me a while to get into the other 12 songs. Now I find myself struggling to get into any other Fugazi album, but this is one of my favorites.
Superchunk - Foolish
Now it is my favorite Superchunk release, but upon first listen I was disappointed that I didn't hear any instantly golden singles like 'Slack Mother****er' or 'Hyper Enough'. But rest assured, after five to six listens the first half really started to open up. I think it is very consistent throughout.
Modest Mouse - Lonesome Crowded West
I have always loved
Good News, but this one took a little longer. One day in the car it just "clicked", and oh boy is it good. After listening to the rest of there catalog I can see why this is considered the defining album for this band...