Well, personally, I went through a time where I wasn't sure and was bi -- I'd say now I'm more so on the lesbian side. Although, from time to time, I might find a guy attractive, relationships and sexual stuff doesn't seem to work/fit when I'm with men. I do not know if the sexual part will change after surgery, because I've heard that for some people it does.
Personally, I just think of myself as myself, and if I fall in love with someone, regardless of gender, I'm fine with that. I tend to be mostly attracted to women, but not girly-girly women. The men that I sometimes feel an attraction to are a bit on the fem side. And again, attraction vs an actual relationship and sexual encounter is different.
I've been with both, including other trans people, and for me being with another woman seems to feel more comfortable. Also, hanging out with lesbians I seem to be pretty comfortable, too, and I feel that I'm being more myself. I'm girlish, but not high fem. I usually don't wear skirts/dresses unless it's an occasion. I don't always wear make up (these days, make up is almost an occasion), and sometimes I'm a bit tomboyish. So, a lot like the other lesbians I know. And I'm find with that.
--natalie