ack is a great "programmer's grep" tool. If you don't already use it, check it out. Now, ack is packaged as part of Debian Testing (Lenny), but unfortunately there's a name conflict. Debian already ships a Kanji code converter named ack, so the ack that I want gets renamed to ack-grep.
I want to run 'ack' on all my systems, not 'ack' on some and 'ack-grep' on others, so I abused Debian's 'alternatives' system to let me do this with:
update-alternatives --install ack ack /usr/bin/ack-grep 100
And voila, it creates me a /usr/bin/ack that Just Works, and is known to Debian so future packages won't (I hope) break that symlink.