So, back from the Linux jungle and sitting in front of a Macbook once again.
My first real job has been to get a decent unix environment up. OSX's BSD utilities don't really cut it. Macports is far and away the best distribution out there.
Once you install coreutils and get ls, find etc it makes sense you will want to change your shell to a modern version of bash (or zsh if that's the way you roll).
Lion ships with bash 3.2 whereas Macports will give you a contemporary version 4.2 Unfortunately it's not as simple as going
$ sudo port install bash
I had to do this before, but I'd forgotten there's a trick to changing your shell in OSX to a non-standard location. The file /etc/shells contains a list of valid shells chsh will permit. You need to edit (as root or via sudo) this file and add your macports shells. Once that's done chsh will let you change no problem.