I read a lot of PDFs. In fact most of my time at the computer I spend reading PDFs. I read documentation, datasheets and lots of school stuff, so this definitely requires a good choice of a PDF reader.
Because I'm also a user of XMonad, just opening a PDF reader and reading a document is not what satisfies me. I need a sensible way to organize opened documents and a quick way of opening just downloaded files.
For the last couple of years I've been succesfully using xpdf - the reader which remained my favourite for a pretty long time. Unfortunately, recently gentoo dropped support for it, because of its bugginess and stalled development (or no development at all:D), so after some time of providing my own ebuilds, when it failed to start after a poppler upgrade, I decided to search for something else.