Interesting article. I'm sure there's lots more than can be done to make the shell an even more productive working environment.
I've written a Bash script that adds colour to shell output, cycling through colours one per command. I find this really useful when I run something like "make" and it generates loads of output. If you want to scroll back to the start of this command's output normally it's hard to spot where this command started, but with colours it's easy. You can get the script here: http://chezphil.org/colourshell/ (US readers note the spelling!).
There must be lots of other stuff like this out there in peoples' ~/bin directories that could be useful to others - please share!