This may have been asked, but doesn't seem to have been asked lately. I am single and have been for several years. I'm happy about it - I consider it my default state and I have to be very motivated and invested in someone else before I consider a relationship. Other single people I know seem less satisfied with their status quo overall, but I don't know anyone who is miserable about it.
With all one hears from the media and acquaintances, it's accepted wisdom that single people, and especially women, are dissatisfied with their status. On that note, I wanted to start a poll.