Squeezeboxes are AMAZING. I have 7 of them in my home, and with a few button-presses, they can all be synchronized for whole-house audio. Also the server is open-source (Perl) and you can create your own plug-ins. I'm using plug-ins for faster search, logging of all tracks played, and creation of sync groups (so with one press, you can, say, set all your upstairs squeezeboxes to play one tune and all the downstairs ones another tune). Some squeezeboxes have built-in speakers (the Boom) and others require a stereo system. I have never regretted buying them. For the ultimate in space-efficiency, you can connect a speakerless squeezebox (e.g., the Classic) to a tiny in-wall amplifier (www.wireless-experts.com) that fits into a lightswitch box, connected to wall-mounted speakers. All people see is the squeezebox, the speakers, and a volume knob on the wall. Nice.

Two techniques I particularly remember for increasing my Linux effectiveness were:

1. find piped into xargs (or "find -print0" piped into "xargs -0" for safety) to process a directory tree in a single command

2. Printing commands on stdout and piping them into bash. For example, if you want to rename a bunch of files, and you put the old names into file "oldnames" and the new names into "newnames", one per line, you can do the mass renaming with:

$ paste oldnames newnames | sed 's/^/mv /' | bash

generates a sequence of "mv" commands and executes them.

First time I saw each of these, it was so eye-opening.