The Conservative Deist/Fists in the Wind has a good post about teachers' responsibilities in the classroom, especially as pertains to not trying to browbeat or indoctrinate one's students. I'm not sure what my students think these days, but when I was a TA, I found out (through direct polling after philosophy of religion units) that about half of my students thought I was a gung-ho atheist, and about half thought I was a devout believer. I have never known quite what to make of that result: is it a good result because of the even split, or a bad result because virtually everyone thought my beliefs were polar?
These days, I'm experimenting more with letting my own thoughts out into the classroom, but I find I tend to do so only when my thoughts are either (i) so tentative that my students and I effectively are in the same boat, working together to try to figure things out, or (ii) so counterintuitive that all of my students effectively are working together to try to knock me down. They appear to benefit from both variations—I know I certainly do.