I identify with a lot of what the OP wrote. Lifelong depression, relating better to women than to men, feeling nothing but distaste for "masculinity," feeling like some kind of alien life form when I'm among people.
On the other hand, I've never felt this overwhelming need to become female (-- yet.) I mostly just don't want anything to do with the male role, and envy that certain way women (mostly) accept other women and never accept men. I also tell myself it's impossible, anyway, because the best I could hope for is to become a half-assed imitation of a woman.
On yet another hand, I often wish I'd been born a woman -- there are so many things that women get to do and to be that I've had impressed upon me are forbidden to men. (And, yes, I know that women face all kinds of restrictions and oppressions that I, living as a man, never have to deal with. Maybe if I'd been born a woman, I'd be wishing I were a man.) When I was a child, I was terrified by stories in which a boy becomes a girl, but I think what I was actually terrified by was a wish that I could be transformed, a wish that was so forbidden I had to hide it even from myself. Over the past ~10 years or so, I've gotten to the point of wearing skirts and jumpers ("pinafores", for you Brits) and sometimes dresses most of the time, and when I put on pants, I feel like I'm in drag. (I'd wear women's blouses if I could find ones that actually fit me. Maybe when my sewing skills get good enough, I'll make some, the way I make my own skirts &c.) So my presentation is mixed -- female clothes with a male body.
I don't know what to call myself. If I call myself "transgender," it feels like I'm "appropriating" the experience of Real Transsexuals(tm). I used to think of myself as a cross-dresser, but every CDing forum I've visited just turns me off -- their attitude towards women, towards "femininity," and towards what they do is as alien to me as the stereotypical male locker room conversation. I feel a lot more at home in the discussion fora for transgendered and transsexuals, even though I don't think I am one. (Just as I feel a lot more at home in discussion groups by and for women than for groups for men -- or for mixed genders, either, since they usually end up being male-dominated.) I've been hanging out in the androgyn section, but I don't feel any particular attraction to androgyny (though the people there are nice.)