The Mortal Instruments Series
I purchased the first three books in the Mortal Instruments series a couple of years ago because every single one of my reading buddies had read it and absolutely loved it. I trusted their opinions enough that I went ahead and bought all three that were out, but I just never made the time to read them. I don't know why. I really don't. I see them sitting on my shelf every day but I just haven't had any desire to read them yet.
Have you ever purchased books that you really wanted at the time and just let them sit on your shelf instead of reading them?