1) Voice. This is number one because basically no matter what someone looks like, they will be attractive fullstop if they have an attractive voice. (This is for me, at least.) Although I probably wouldn't insist on a great voice in a guy if it was the only thing wanting, there's something about a deep voice, or a British or Irish accent, or a charismatic voice, or a persuasive voice that makes me want to go "Ooh, please, please, can I have your babies??" ... only silently!
2) Eyes. Boring choice because this would be near the top of basically everyone's list. I always feel very sorry for those actors who always have to play the bad guys because even if they're dashingly handsome and attractively dangerous, they usually have scary slash nasty eyes and I'm not sure they'd be able to find a nice girl.
3) Smile. Again, probably a boring choice. I'd rather they weren't always grinning - it would make me feel so colourless and depressed. But if they occasionally let out a smile that transforms their face, it makes me intrigued. And, as everyone knows, people with nice smiles are ALWAYS trustworthy. (They really shouldn't let me travel.)
4) Hair, or lack thereof. Please don't look at the above picture as an example; I just chose it because it looks funny. But I do like dark hair, and I also don't mind a bald head occasionally. I'd rather guys shaved it all off than had a bald spot or - most tragic of all - a COMBOVER. Having said all that, I wouldn't repulse a blonde guy for no better reason than he didn't have dark hair, but it wouldn't occur to me to like him for quite a long time, probably.
5) Height. Okay, so not so extreme as that. But I'm a tall girl and I hate feeling like I'm dwarfing one of the male species. On the other hand, if I'm standing next to a very tall man, I feel agreeably petite. :)
Do you have a list of your own?