We might be building (mostly) analog electronics, but there's surely times when some computing power can help us, I'm guessing you didn't receive this page as a print out ;)

I've actually yet to use the oscilloscope software linked to below, but I've heard good things about it and "real" oscilloscopes are still prohibitively expensive unless you happen to walk by when someone is throwing one out.

Unless you prefer drawing your layouts with etch resist pens directly on the copper, you'll most likely want some software for drawing layouts. DIYLC (or Do It Yourself Layout Creator) is a stable and nice software for drawing your layouts. Low barrier to entry and quite possible to draw really nice layouts with it. Do check out my DIYLC Tutorial and my Perrow Style DIYLC PCBs tutorial for drawing curly layouts.

Sound card oscilloscope - Free for non commercial use.
DIYLC - The layout program that I use to do all my layouts.