I'll sign on as "happily TG."
I'm definitely on the gender spectrum, not at either end. We keep saying that sex is different than gender and so I am happy to accept that my sex is male, but my gender is -- complicated.
Katey's OP brings up an interesting thing about the TG experience: the visual aspect. That's a key to me as well. Humans are programmed to recognize other humans and we have a sense of what's right about them or wrong when we look at them. There was a thread a while back about how you felt when you first saw "her" in the mirror. To me, the first time I saw "her" in me there was a shock of recognition. That was who I was. The person I had been seeing in the mirror up to then was not.
Now I phrase that as two personalities in one body staring across at themselves, but that's not what I feel. I feel I'm me at all times. At first we don't have the vocabulary to express what we're feeling so often we carve out two personalities since that fits our vocabulary -- there's Patrick who is male and Jennie who is female. But as I learned more (and much from this site) I realized I was always the same person. And I started losing my obsession with "passing" when I crossdressed. Now I'm actually happier that I'll never be mistaken as a real, genetic woman -- that's not what I want people to see. I want them to see a man presenting female (and looking damn good) and being happy with that in-between state. Sex = male / Gender = other.
Achieving the shock of recognition had another side effect -- suddenly I cared about me. Viewed in retrospect I think my previous life could be viewed as long-form suicide attempt. I didn't like the male gender-acting me. So I was a slob -- who cares what he looks like? I was overweight. I was diabetic. I wore clothes that were older than my kids (eldest is 27 at this writing.) Now I care. I dropped 50-ish pounds, my diabetes is asymptomatic and I rarely make it though a week without buying some new bit of clothing that I'm excited to wear. In the morning the first word out of my mouth used to be Crap !!! I was sad to be alive. And now I wake up and wonder what's the perfect thing to wear today?
Sorry -- probably TMI, huh? Here's another observation about the visual aspect though -- and I think it argues that we're recognizing ourselves when we crossdress -- some people say that crossdressers are looking for attention or are closeted gays trying to attract men. We can look at our own closeted cousins and dispute that, I think. Certainly if you read through some of the heartbreaking testimony of what our closeted brethren do to avoid detection you can refute that they're doing it for attention. And since they are closeted or hyper-closeted they're not trying to attract men. They're trying to attract themselves. And certainly when I dress I choose my outfit with some sense of what activity I'm going to be engaging in, but more than anything else, I'm looking to make me happy. (Which interestingly squares up perfectly with what women have always said about their own dressing when the men start trying to shame them for provocative dressing. "It's not for you, it's for me!" they say.)
Is it all visual? Probably not. Underdressers hide what they're wearing. Their enjoyment is in their heads. They don't go past the mirror a hundred times a day to say to themselves "I do her..." It's the knowledge that they're wearing panties or knee-highs or whatever that's driving them. That's filling in the little empty spot that forms when someone on the spectrum tries to pretend he's living at one end.
Now, I have TS friends. I have a TS girlfriend who finished her transition more than a decade ago. I have no doubt in my mind that they are not like whatever I am. The ones I know are definitely women top-to-bottom, front-to-back, every day of their lives. They are TG according to the definition, but they're not TG like I am.
And another thing.... oh! look a bunny!