List the installed shells
[...]$ chsh --list
Change the default shell used
[...]$ chsh -s <path>
[...]$ chsh -s /bin/bash
Would be cool if you also gave some guidelines on choosing an alternative shell. Many people advocate for zsh but I just never thought about why would I want to change my default shell...
Personally i don't have a fundamented response for your question.
I have been using bash shell for all the time and now i'm trying out zshell. I like some great features from zshell like directory stack and his brace expansion but for me it's too soon to compare each other.
ZSH is my choice, because it has a lot of nice features already build in. Of course, this makes it highly complex and rather hard to configure. But it's worth it!
Most distributions (eg Ubuntu and Arch) have an zsh-lovers packages, which contains a man page with alot of nice and useful examples.