I hope they make ZSH the standard shell. It's similar enough to bash to not disrupt most workflows and Apple has been able to update it due to its permissive license.

I use ZSH as my main shell on OS X. I find it superior to bash in almost every way (especially with oh-my-zsh) except in ubiquity. Even so, I have no problem using bash if that's all that's available, the two shells are fairly compatible.