I'll sing when I'm on my own or my girlfriend's the only one around or perhaps when I'm drunk. That's the only times I'll do "lead vocals" ..
My girlfriend says she likes my voice, but I don't really like to hear myself on recordings much and I have very little confidence in myself and singing (plus - girlfriends have to be biased anyways, so why trust her?). I'm quite able to sing, but I'm just not convinced that my voice sounds good.
Other than that, I do backing vocals now and then in bands, live and on recordings .. I'm fine with not being so up-front.
I've no idea what my range is. Good enough to sing along to most of the music I like.