I love the selection at Eliot's. There's a huge selection, and some of the most random books you can find there, ever. I spend a huge time on the third floor. I found a diary of a lady who had moved to Canada in the 1920s. There were several volumes, and feeling extremely poor at the time, I could not buy it.
It can be a little dusty, and there is that slight smell of decaying books, but I could not have it any other way.
It's my go-to place for research when I'm writing stories. The old man that's there sometimes is always very friendly, and he is super happy when you walk out with a bunch of books.