That and 12 or 13px Verdana is the way to go in terms of a good combination of readability and space efficiency (if required).
If you don't know my OS settings, my browser font default (which on my system, some browsers like Firefox will inherit from my Desktop Application settings while others such as Opera will not) or my resolution, you wouldn't be safe with 12 or 13px, even with verdana (which isn't default on Linux machines anyway).
Since setting a % font size on the body removes an IE resizing bug, I feel really safe doing this:
font: 100% verdana, "lucida grande", "dejavu sans", sans-serif;
and can in the body text set line-height (otherwise you get whatever the browser-default is).
Jon's colour checker is good. I use Gez Lemon's Accessibility toolbar which has a Colour Contrast Analyser built in (and you can check for A, AA, and AAA compliance). If Canada follows WCAG then they may use the A-AAA rating system... but I dunno that they do.
As an official non-old-fart, I resize text regularly, but less so than before I increased my Desktop and Terminal sizes.