I think it is really hot when a woman gets undressed out of order. For instance I find it sexy if a woman is bottom half naked but top half clothed or partially clothed. Sex like that is really hot. I like breasts, but I find intercourse while my partner has a bra on to be very sexy. It doesn't have to be fancy lingerie, a t-shirt is good, but stockings and garters are hot as well. I think the inconcruousness is what is hot, as well as the connection between the person she is during the day with the person she is having sex. Whatever it is, I think that it is erotic. One variation that I have heard of is for women to wear sunglasses or regular glasses while having sex, especially while giving fellatio. Havn't tried that one yet. I hope that ives you some ideas.
I like to have little outfits on for my bf when he gets him from work. He likes it too and his friends tell him that he is spoiled because I do it for him often. My bf also likes short dresses or skirts with no panties on and then for me to bend over in front of him. These are not necessary for him to get excited but just make it more fun.
My fiancee doesn't need any special clothes to look at, so I can't help you there! Some guys don't need any extra visual eye candy to get aroused.
I would look around on the internet to see about extra ideas. I just don't have much, since my guy is happy with just about anything! lol
-phat