I'm not but I have a few friends who are. Whether that affects how I feel about them depends on what kind of virgin they are.
There are two major kinds I've encountered. The first are the laid back, "I haven't had sex yet but meh" types, I can respect that and it doesn't affect my opinion about them one bit. Some people choose not to have sex, others just haven't met the right person or had the opportunity come up. Fair enough.
The second are the self-entitled, "Why won't anybody love me?!" kind. They want sex, not a relationship but just sex, with anyone, anywhere, just so they can say they have. They might even be mildly attractive, heck I've seen worse get laid. But their attitude and constant passive aggressive demand for attention drives people away and makes them socially inept. What bugs me the most however is their sense of entitlement. They always blame others for their situation, it's never them. And they think that just acting nice around women should result in sex, they treat them like objectives instead of human beings and call them greedy or selfish when it doesn't work. There's no reasoning with them, I've tried both the touchy feely don't-hurt-their-feelings approach, and the tough love hit-them-with-reality one too. It all just bounces right off of them, it's like talking to a brick wall. They refuse to change, they sit there and expect the world to change for them.
The ironic thing is that the people in the first category always end up having sex, and often getting into awesome relationships. But I know people from the second category in their mid-thirties who still haven't been laid, and instead of wising up they just whine even more, until they've alienated and worn out the pity of every person who tried to help them.