I'm OCD about so very little in my life. Very, very, very little. However, there are a few little ones. I like frames to be straight. All the time. Can't sleep if they aren't, no matter the amount of clothes on the floor. I also alphabetize DVDs and CDs. It's the only way that I can deal with the quantity I own. (CDs are by the last name of the artist, and DVDs are by the title of the work for the most part.) The only other one I can think of is that when I put food in the cabinet, I like it to be label out. I'm sure there are other weird little things, but I guess we don't always think of our own habits as odd.
I'll be anxious to see how everyone else answers this one! Make sure to link up!