Gorgeouskitten, thanks for responding. After our night together I figured there wasn't much point trying to hide my feelings anymore, she's a perceptive person and she knows me very well, she knew nothing would have happened if I wasn't interested in her no matter how drunk I was. Although I didn't drop the L word, I did discuss my feelings for her and she was pretty supportive, which was nice to know it wouldn't come between us. She's pansexual, so our genders weren't an issue for us, she just doesn't return my feelings.
As far as trying to figure out what about her turned me on, I'm trying to think of what that could be and I'm not coming up with any specific traits, just her as a person. I could mentally superimpose any of the things I like about her onto someone else and it just does nothing for me, but thinking about her is entirely different. Does that make sense?