The classes I've enjoyed most would probably be my philosophy classes, despite the fact that I'm an english major. Especially the classes taught by one particular professor, Intro To Modern Philosophy and Topics In Aesthetics (which I'm taking now). I also have taken a few courses on Greek philosophy and one on philosophy in the High Middle Ages (basically, mostly Mid-Eastern post-Aristotelian philosophy, largely attempting to justify religious beliefs). The Greek classes were for the most part very enjoyable, but the latter class was extremely difficult and the teacher was uncompromising and frustrating to work with. I got a B, which I think was the highest anyone got from that guy.
As far as within my major goes, my favorite classes so far have probably been those focused on Victorian literature and Shakespeare, the latter of which I'm taking now. I've grown to be rather fond of the Victorian tradition, especially of Dickens of course, as well as of George Eliot.
My least favorite classes would be no contest: Physiological Psychology and Intro To Logic. Neither course was anything like I expected it to be, which of course is my fault for not researching them, but nonetheless it grants them the status as the worst fucking classes I've taken as of yet. The former turned into a Biology and Anatomy class more or less, when I was expecting more typical Psychology, the latter turned into a Math class, which I've been trying to move away from, when I was expecting something more along the lines of Philosophy. Needless to say, these are the only classes in which I've gotten lower than a B, and they were in the same semester, so that was a real shitty time.