Nope, I don't have any of them filled up. While I like to keep a lot of books on them so that I can read whatever genre might strike my fancy at the moment, I've found that there reaches a certain point after a few hundred where I just don't remember what specifically about a story made me think that I would find it interesting, especially when it's a one-off book by an unknown author, no matter how many tags I add to it.
What I do like putting on the ereader is the complete oeuvre of a favorite author, especially one that I tend to reread in full every few years. Makes it very convenient.