Physically, there are all sorts that I find attractive. I do find athletic bodies with well-defined muscles very attractive, but often the brain inhabiting those bodies to be less so. I often seem to like guys with darker skin and hair and who have a bit of 5 o'clock shadow. Although there guys I find attractive who don't fit that description at all, so it's not a hard-and-fast rule. I really don't like tattoos and piercings.
What, for me, changes things from finding someone attractive to whether I really like them is very much personality. I definitely go for smart, motivated guys and for guys who are accomplished. Looking at the three guys I've had serious things for (not that any of them actually went anywhere), they were all slightly older than me and were all excelling in some aspect of life that I was concerned about at that time. So, for example, right now I'm in the process of applying to grad schools and choosing which ones are my preference. The guy I most recently had a crush on (well, still do to some extent, but less so now) is a postdoc, just a year out of prestigious grad school. He is clearly extremely smart and is excelling in his research. As an added bonus, because we have similar educational backgrounds, we can talk about technical, research-related topics (which has not been the case with any of the guys I've been on dates with). All of these things made (make...) him extremely attractive to me and were far more important than his looks (which, if I'm being honest with myself, are nothing special).
I've got to say, too, that my feelings for a guy will really only start to develop fully if I find out he's gay to. If I think he's straight then I can sort of keep a lid on them--I'll feel an attraction but nothing major. Once I know he's gay then all of the feelings seem to spring out on me. This was certainly the case with the last guy. (If you're wondering why I haven't acted on my feelings, I actually did. I asked him out for coffee, but he let me know that he's already in a relationship.
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