The way I remember it, transvestite used to be the main term for someone "posing" (I use the term in as wide as possible a sense) as the opposite sex, applying both to dudes who just liked wearing women's clothing and people who actually wanted to be a different gender, then transsexual was introduced to emphasise more on the desiring a different identity side of things, and then we ended up with transgender which was introduced to emphasise the difference between sex (physical/genetic identity) and gender (social/psychological identity). And I'm pretty sure all this mostly happened in the last 30-40 years, so it's not too strange that a lot of us are confused or not entirely in agreement over what is what.
I do know that some people have continued to use the term, but as mattius77 said, "cross-dressing" seems to be the more acceptable term for someone who just happens to enjoy using women's clothing without necessarily adopting an entirely female identity, because for a lot of people "transvestitism" seems to bring associations to either what we now call transgender/transsexual, or to sexual fetishes, and not all cross-dressers necessarily to it for kink-reasons. For example British comedian Eddie Izzard.
Anyway, I just wanted to say I'm positively surprised over the civility of responses on that comment. I'm used to seeing things go south pretty fucking fast as soon as someone gets a bit "real" on these kinds of topics.