Saying what you mean in your ad or profile: sexy
No one who's been following this discussion will be surprised to learn that I'm rarely impressed by someone who describes himself as sexy or specifies that he wants the object of his affections to be sexy. Are we playing the obvious game, or what?
"Sexy", like "fun" or "cool", is meaningless. Of course each person wants to hook up with someone sexy, but what's sexy to you may be a huge turnoff to me. The whole point in posting a profile on a dating site or an ad on Craig's List is to catch someone's attention and convince them that you'll be a good match. One of the ways to do that is to explain what you find sexy so that she can say to herself, "Hey, look, here's a guy who wants someone like me!" And on the flip side, you can describe what's sexy about yourself so that that special woman out there who has a fetish for gangly, freckled guys will be sure to write you.
The more explicit and creative you can be, the more you stand out, and the more you stand out, the more interesting you will be. (Okay, that's an oversimplification. There are lots of ways to stand out in a bad way, but if you've been paying attention, most of those should be easy to avoid.) What catches my eye is creativity, and using "sexy" doesn't score that point by a long shot.