albo - 3:03 am on Feb 4, 2010 (gmt 0)
My doc sez 20-15 in the left eye and 20-25 in the right. So...
My old codger clients prefer (believe it or don't) Lucida Grande to Verdana for plain text: Verdana's so fat it makes a blur for lines longer than, say, 25-30em. They prefer, too, some "font play". Palatino/Georgia or Times for headers, and, yes, Verdana for small footer/about-the-site.
I use % sizing because an em of Verdana is different from an em of Palatino and it gets too tricky, mixing back and forth.