Half tights are great. I wear them more and more as I get a little older. (Still only in my mid twenties but find my legs don't like anything fast if it's below 40 or so anymore without half tights) I've only raced in them once but it was below zero. Anyway, I for one, have gotten past the fact that they look really bad, all I care is that they are functional. My girlfriend hates them, but she's still with me (at least last time I checked), and she's pretty cute.
Anyway, as far as the other issues discussed, shorts over half tights make you look like an insecure high school kid, if you're ok with that, then go for it. Capri's make you look like a girl, if you're ok with that, good for you.
Also, not that it matters but I'd be willing to bet that I'm faster than the OP at Mile, 3k and 5k, probably 10k too. And besides, Bolota Asmeron rocks speed suits in 5k's and he's got an A standard.
So here it is, if you're not secure enough to wear them, then don't, I prefer them to hamstring or quad issues from running fast in cold weather, and I refuse to look like an insecure high school kid, that ended 7 or 8 years ago.