Funny, I use bash for almost exactly the same reasons a lot of people here use ksh. I like being able to quickly switch between emacs and vi-style modes (I use emacs for everyday stuff and vi for editing big multiline stuctures). Bash also has some really nice expansion features like being able to say "mkdir directory{0..9}" and create ten directories.

I'm sure all of what I'm describing can also be done easily with ksh as well -- it's just a matter of what syntax I'm comfy with.