Well, I can't exactly justify having preferences for guys considering the closest I've ever come to a romantic relationship was this kid who asked me out in 8th grade, who turned out to be homosexual. You can be sure that did wonders for my self-esteem. Either way, if I had to think of quirky traits (though none of them are particularly quirky), I'd have to say that I find height fairly attractive. Taller than me, but not too tall. This is not difficult as, at 5'5", I'm just a few inches too tall to be classified as a pygmy where I'm from. This and darker colored hair.
Also, tattoos are awesome. My mother hails from New Zealand, so, earlier on in my youth, I was raised to understand tattoos as not only a source of endless attraction, but also as a right of passage. However, these things are optional. The only necessities would have to be a tolerance for:
a) my personality. I can be rather outspoken, unintelligent, and generally obnoxious at times. I always try to inject whatever statement I'm making with at least a semblance of intelligence, but the results are not always satisfactory. It sucks, but there's little I can do to fix it, and damned if I'm going to try for someone who isn't interested in what I already am....They also have to tolerate stubbornness.
b) the grating, ear-raping travesty that is my voice. It's deeper than most females, at times it's shrill, and when I laugh, I've been known to deafen everything within a 5m radius.
c) my music. I'm a guitarist. That's what I am. I've spent endless hours drooling over the classical stylings of Andres Segovia as well as the general awesomeness of Malmsteen, and have dedicated over 70% of my life to the instrument. If he can't deal with the frustrated and, often profane cursing (sometimes I actually play them as well) of my guitars in the ungodly hours of the morning, we have a problem.
Also, he must be in possession of at least one piece of H.P. Lovecraft paraphernalia, or something of the like.