I don't know how to rate things. In a world with Labyrinth Books, Powell's, and Capitol Hill Books, why do I rate every good bookstore as five stars? Because this isn't the restaurant world. Great bookstores deserve superlative reviews because it is a herculean task to keep a bookstore open these days.
Caliban's is easily the best bookstore in Pittsburgh. It has a terrific vinyl collection, some lovely prints, and oh DO NOT FORGET TO GO DOWNSTAIRS. That is where all the paperbacks are. It took me several visits to figure it out (yes I am embarrassed but I see other reviewers made the same mistake so I want to be sure other visitors have the best experience possible). Their history and philosophy section is phenomenal. They have some very, very nice first editions which I cannot possibly afford, but they have so many good, affordable editions of those same books that there's no cause to complain. This isn't just a shop for antique collectors. Also, I like the stuff they're always playing in there.
On the wish list? I wish it was bigger. And served pie. But that's pretty much my wish list for every bookstore, so ignore me.