Quoth the raven named Jim Royal:
I've been wondering about the fashion these days to tell people not
to specify font sizes on their web pages. Frankly, I don't consider
this very good advice.[/QUOTE]
An author is supposed to please his/her visitors, who are in charge.
The fact is, no matter which font size you pick, someone will want
to resize it. So you might as well pick the one that works best for
the page.
...or not pick any.
If the designer specifies no font size, the default size will
appear too large for the majority of people, who will all want to
resize the text (if they know how to do it, which is not a given).
Notice that the OP asked "11px or 12px Verdana." The crux of the
problem is the choice of Verdana. It's too big to start. Therefore,
authors tend to set a smaller px size to compensate.
What happens when I visit with my computer that does not have Verdana
installed? I get my default regularly sized font way too small.
If the designer specifies a reasonable font size (such as 0.9em),
this will be readable for the majority of people.
...who have Verdana.
Those who need
bigger fonts can still resize the text, but far fewer people are
inconvenienced.
If you design your site correctly, using my default size (100%) and
only specify { font-family: sans-serif; } you are catering to me, your
valuable visitor, rather than your own personal taste. Naturally,
you've checked your site in several browsers to make sure that
increasing or decreasing font size, and using various common and
not-so-common fonts of any size, to make sure the design doesn't break.
And remember, as stated so often, visitors with that famous operating
system component masquerading as a browser, will not easily be able to
up the font size for your site if you specified pixels.
Go to the site I referenced (freezeblock.com) and change your default
font to whatever you have available (for English) and whatever size
you want to try. Doesn't matter the window size either. Except for
graphics and some button overlap, it works at a PDA size of 240x320
screen, and it even works reasonably well on WebTV.