I have a soft spot for antiheros. I will, inevitably, read any book I hear of that has an antihero in it. I may not end up loving the book once it is read, but chances are, you say "antihero," I will jump to read what it is you are talking about.
One of the reasons I love antiheros so much is because (in my opinion) they are characters that seem to be very hard for authors to do well (they are either done really well or just fail miserably), so when there is a well done antihero, it's like brain candy to me. Well written antiheros tend to be very three dimensional. Authors give these characters a lot of thought, where they may not need to give quite as much thought and depth to characters who are strictly good or bad morally.
Another reason I love these characters so much is because, in my view, antiheros tend to reflect the real world more than characters that are strictly "good" or "evil." I don't, personally, believe that strict "good" or "evil" exists in our world. Everything seems to take on varying shades of gray based on perception, and antiheros seem to reflect that reality more than other morally persuaded characters would.
Thus, antiheros are one of my literary soft spots. I am almost always guaranteed to read a book with an antihero in it, and enjoy it in some measure because of what I stated above.
Do you have a literary soft spot and if so, what is it?