Julia Serano REALLY destroys this notion of stratifying trans people based on their genital configuration in "Whipping Girl." When others "gender" us, they do so almost entirely based upon secondary sexual characteristics. As she says, "really, how many times have you actually seen another person's genitals during your day-to-day life?"
She also makes the point that reducing "womanhood" down to whether or not you have a vagina is also misogynist, because it relies on the assumption that a woman's worth is tied to whether a hetero-normative man would sexually desire her. This view point is also classist, because many trans women may never be able to afford the full-on "bottom surgery," even if they want it.
From my point of view, as someone who is undecided on if I will ever go the full SRS/GRS route, I'm pretty sure that a few years from now, when I look in the mirror and see a pretty girl staring back at me, and (hopefully) the world treats me as such, I'll feel like a woman... even if, to quote Serano, I have a "tiny, estrogenized penis" cowering in my boy shorts. 🙂