Attraction is such a funny thing. No two people agree 100% on what is and isn't attractive to them, and that's OK. It's what makes it great, to know that in this one things, each of are individuals. I read an article once that said people emit pheromones, just like a lot of other animals do, though we don't really pick up on it. It said that this accounts for that instant chemistry some people have, where they meet someone and automatically are attracted to them (this same article also said that family members' pheromones indicate 'family' to us, which is why most "normal" people don't sleep with their parents or their children, because the pheromones tell us that it's wrong; not sure if that's true or not, but it made for a good read).
And sometimes you meet someone, and even though physically they are your "type", for some reason you don't think of them that way. Whether it's because you see them as just a friend, or that you feel that there's something off about them, you just can't picture kissing that person, much less being naked with them (or touching naughty bits, for those that might say that you can have a quickie with a stranger with your clothes on).
One of the nice things about getting older (besides, you know, not being dead) is how you can still picture an ideal mate (i.e. your fantasy mate) but can accept that reality is much different. I will use myself for an example.
Obviously, since I'm on this site, I have a thing for beautiful women who are considered "alternative" to the mainstream (though that line blurs more and more each year, which is a good thing): tattooed, pierced, colored hair. Also, most of them are fairly liberal and quite often, geeky in some way. So, yes this would be my fantasy, to be able to be with someone like that.
Now, here comes the reality. I am a 41 year old author and a father of 3. I'm not made of money, and my writing career is just starting to take off, so it's not like I'm famous or anything like that. The types of ladies I'm attracted to (the fantasy) are usually younger than myself, and not really interested in a guy who's idea of a good time is either going out to a bar and having dinner and shooting a few games of pool or curled up at home, playing video games or watching movies. If they are, they're not single or they don't live anywhere near me. Which is OK.
Another great part of getting older is being comfortable in your own skin, being able to admit your faults and things of that nature. I realize that I myself am no one's "fantasy", and that's OK. (this isn't about garnering any pity, or anything like that). Instead, I look for women who are into the things I am, even though they may be a little older and not really tattooed or pierced or have colored hair (the fairly liberal thing, along with being geeky, are non-negotiable LOL). Because at the end of the day, while a fantasy can get your blood pumping and your heart pounding, having someone really there in front of you should trump that, every time. But then again, what do I know? :)