Well, for me, there are two answers to this question...
Essentially, none. On the base of it, I find makeup to be extremely artifical looking and senseless, not to mention that someone wearing it every day screams low self-esteem to me or, at the very least, so little self-awareness so as to not recognize that they can, in most cases, look just fine while rejecting the socialization that has been thrust upon them.
So, when looking for a girl, I'm looking for someone who doesn't wear makeup often. Someone who not even once says that they have to put on their makeup to do something.
There are a few key elements to my consideration of makeup in this regard then. First, is that makeup when worn should never be "not noticable." Makeup that is "not noticable" is the equivalent of using it to cover up perceived flaws, otherwise where is the need to wear it in a style that is not readily apparent? I don't like makeup ever used to cover up "flaws" but only, when worn, to enhance, or create an "image."
Then, there is the fact that some items of makeup I don't like at all. One, is any sort of base or foundation. There are essentially 2 reasons to this one. First, there is no use for it besides "covering up." The only way in which to wear it in accordance with my first consideration of makeup - being intentionally noticable - is to wear something like white foundation. *shrug* if someone wants to do that that's fine, but I don't find that attractive and there's also the problem of the second reason of disliking foundation: why would I want to kiss makeup? When I kiss a gil, I want to feel - physically and intellectually - that I am kissing HER not the makeup she's wearing. So, while foundation IMO shouldn't be "not noticable," there's a problem if it's noticable too, so I'm always against the foundation.
Eyebrow pencils: no. Looks tacky first of all, looks just plain stupid second of all, and really, I don't even fathom the point of it.
So, what DO I like with makeup? Well, I DEFINITELY DEFINITELY like the dark eyes. They rock. It's not makeup worn to make up for some perceived flaw in the length of eyelashes or anything like that, it is worn specifically for the sake of itself. In this sense, it becomes more like clothing than makeup. And I think it looks sexy. Looks best with black or dark brunette hair, but also looks really good with very light blonde hair.
Second to the very dark eyes is colored eyes. Green and purple are both cool colors for this. Example: Marion in Requiem for a Dream. Her eye makeup if I remember correctly was quite cool in some scenes in that movie.
As for lipstick, I'm not generally a big fan of lipstick and I really only would like it when someone is going that extra step to look really made up. Probably the only circumstances I'd like lipstick is something like clubbing, where everyone essentially works hard to look their sluttiest/sexiest (depending on different people's interpretations) or if you're just putting it on for a special wild night with a significant other. Lipstick in everyday ocurances I'm definitely not down with and, even in formal situations, I find it totally unnecessary.
Lip gloss I am much more leniant on. It can look equally as sexy - and many times even moreso - than lipstick in those situations mentioned above, AND I think it's fine for everyday life as well. Lip gloss is just more laid back to me, so I find it much easier to accept looking at it. Not to mention it's shiny
That's essentially it though. Lip gloss and heavy eye makeup. Anything else is unnecessary/unattractive IMO.
They key to all this of course is that the girl doesn't wear makeup more often than she does. Makeup is something I look at to be used specifically for a noticable, artifical, play into a particular image one is going for. So, in most cases, it's not preferable, but it's great for that every now and then that you're planning on particularly getting someone's "engines" going or even going out and showing yourself off to other people. I guess you could sum it up in the idea that I don't think makeup is something that should be a part of everyday life as much as it should be something more like having a little "dress up" fun