Very useful, thanks ;D
Bash has programmable tab-completion these days. I have a link on my website to Debian's script (it's in Sid, but I'm not sure about Sarge.) It's really nice.
It is in Sarge -- Sarge users can see /etc/bash_completion and /usr/share/doc/bash/README.bash_completion.gz for more info.
'emerge bash-completion' for gentoo.
I played with it back in my LFS days. Interesting but it never really got me hooked