Shells

What shell does /prog/ use?
I've only used bash, but I want to explore my options. So, which shell do you use, and, if you feel so inclined, why?

I'm a Windows developer, and I have some questions about Unix/Linux in general. What exactly is the difference between a kernel, window manager, OS and shell? I see these terms come up all the time, but I'm not sure what they mean.