Concerning the body:
The most important factor in whether I find a woman (physically) attractive or not is her face; I've seen stunning bodies with plain faces and they turn me off, but a pretty face will do it for me for any woman who isn't anorexic, hyper-muscular or morbidly obese. That said, clear skin is also important, as is a bit of body fat - I like a little softness and looseness here and there. Tight skin is a turn-off, but so is skin that begins to fold. I like naturally darker skin or skin that tans well, but I don't like white-girl-got-tanned skin. Beside that, a woman's stomach is also very attractive. A nice, round butt is also nice, of course; for whatever reason, however, legs and breasts aren't really that big of an issue for me.
Although I wouldn't actually think so, experience has shown me to be mostly successful with short, dark-haired women. I don't know if it's unconscious attraction or something else, but there you have it.
I can't stand women who wear bangs, but women who have long hair (braided or cropped or loose or whatever) are nice, as are those who've got well-made dreadlocks. I love dreadlocks on a woman. Tattoos can be really sexy if they're done well, but piercings are a major turn-off for me, except where they can easily be ignored (ears, belly button... yeah, that's about it).
Concerning the soul:
A woman who can take and dish out humor is really attractive in my book, as is one with geeky, "squee!" interests in things like science, animals, language, and pop culture. In general, I find women are sexy if they don't take themselves seriously (in everyday life - I dislike women who don't take themselves seriously in their careers or their dreams), who are playful and willing to goof around. I can't stand people who are just so straight about everything, it irritates me to no end.
I'm also attracted to women who like to think up creative solutions to philosophical or political problems, rather than repeat what people around them say; women who like to explore things with their mind and wonder "What would happen if we did this?". That kind of depth draws me in. But I like women who have the courtesy not to put people down when they correct someone who is wrong or misguided.
I also like women with broad interests that deviate from the norm. Standard barbie girls aren't my type, but neither are standard "alternative" girls - you know the ones, into obscure indie bands and hate globalization and like to sit around coffee shops and smoke. Can't stand them (though sometimes they wear their hair in dreads, and that's a big turn-on for me, so mixed feelings).
I like the girl who catches bugs and puts them in a box to look at, or plays video games (duh), or doodles funny stuff in her textbooks, or likes to watch people on the street and compare them with animals. Someone I can have fun with.