I too quite hate the sound of "transsexual". It
does sound similar to homo- and bisexual, but I don't think people see that as misleading. It's the presence of "sexual" which unnerves me, because my transition's less about my body and more about the relationships I want to have. Sexual organs are just a stepping stone, and one that all trans folk need not clear; "transsexual" brings up a very clear mental image, of a stereotype I'm trying to put out of my mind while I figure out what I need.
"Transgender" feels nicer, so I use that or "trans". Honestly though, I hope the names change some day. As I understand it, they're clumsy labels first applied by
urologists endocrinologists rather than psychologists anyway. Not that I can cite that.
Edit: Thanks for the correction, K8!