The other day my friend remarked that she would remember 2013 as the year when she started regularly wearing jeans instead of dresses. I was actually somewhat surprised I didn't notice since I'd like to consider myself a relatively observant guy. But when I got to asking my male friends about what they like to see women wear, I found I wasn't alone. "Clothes?" one friend offered, somewhat unhelpfully, and then, "But sometimes no clothes?"
The bottom line is that there is no specific item men want to see a woman wear—on dates or otherwise. One friend mentioned that a girl's style should just be "proper for the occasion." If we're going out for fancy drinks or dinner, a cocktail dress is always nice to see. Jeans are great for dive bars and movies. Your work pants, though? Not so much. We don't necessarily want our date to look professional. There's something endearing about a woman who only has the slightest affinity for a sports team but wears their colors to a game. If a woman loves the team and is rabid about her favorite jersey, wearing the piece actually demonstrates loyalty.
There are a few things we don't necessarily want to see out on a date. For example: yoga pants. Those are for yoga and yes you look amazing in them but no they aren't for date night. Also, no Uggs. I have no idea why it turns so many of my guy friends off, but I'm in firm agreement with them; please leave those at home.
All of this being said, we men are simple creatures. One guy said, "Some sighting of skin: legs, neckline, chest, collar bone," is likable. But at the end of the day, the way a woman wears her clothes is much more important than anything else. We want you to be you. One gent told me, "I just want her to express her personality with what she wears; nothing too generic." If that means you're a dress woman and jeans are foreign, that's okay. If you immediately get into sweats and a tee when you're home, we won't hold that against you (unless you come to meet the family in them).
Men are attracted to confidence, not the perfect skirt. Be genuinely yourself, wear something you feel hot in, and we will likely agree. When you dress in a way that makes you feel sexy, you project sexy. And when in doubt, as one friend aptly put it, "A simple black dress would win the day for boy and country in most situations."