Me too. I have an account so that people stop asking me to create an account. However, I've disabled most of the features in the privacy options (my account doesn't even have a "wall") and the only information for visitors is my "about" box asking them to send me an email instead of a Facebook message.
I currently read mails about once or twice a day, because using things like email notifications just interrupts me during work. Regularly checking Facebook updates would be too much noise to me.
I have tons of interesting content that I want to read (but I don't have enough time), so why should I read uninteresting Facebook updates instead? And to socialize I'm happy to get away from my computer, instead of spending even more time before the screen.
I like the picture hosting and the ability to find long lost friends more quickly (although honestly, I don't really have many long lost friends -- and LinkedIn I find better for finding old colleagues), but it's not sticky for me.
I'm probably odd that I'd much rather read about how Logo turtle graphics and JS canvas are isomorphic than read status updates from friends. Not that I don't like knowing what my friends are doing, but its rarely the case that I need up to the minute notification. Once every two weeks is fine. And if there's something big, someone will call or send email.