Besides the obvious sexual attraction that is necessary, I love a Woman who can make me laugh with witty or dry humor. They're always the ones who turn out to be like tigers in the bedroom to IMO.
"It is curious that physical courage should be so common in the world and moral courage so rare." -Mark Twain
Sex is important. Like a woman who is not afraid to initiate that.
But there is clearly more to it than that. Positive attitude is a big plus.
One of the things I find most important is a woman who wants to give and receive affection - hugs, holding hands, I love yous (don't make me turn in my man card, but I think that's important). Maybe it's because that has been missing in my M, and due to the sitch I am forced to think about what I do/don't want if I have to jump back into the dating pool.
Last thing is communication. Again, something that has been missing in my M.