Hoople - 12:37 am on Jul 1, 2013 (gmt 0)
I recently (based on feedback) changed a site I maintain for a non profit group to let the browser/user set the size of the base font (p) and scaled up the H3, H2, H1 from there.
The average age of the users is 70 (not a typo) and the 60-85 y/o's comprise 85% plus of the spenders on their events/fund raising trinkets.
I asked them face-to-face what sites they like the text size of and which they didn't. A majority of the sites they hated were the 'pixel perfect' sites made for 1280x1024 display, which all had the p set to 10px and below size.