Readability of the default fonts in the web browser is one of those seemingly simple questions that isn't all that simple to answer. I will start by saying that is one of the places where fonts were a bit small for my taste, but I'm not sure it's that big of a deal. For one thing it looks like the font being used was different than the current one. I'm thinking it might just be a placeholder. It also seemed like fennec was attempting to do some fancy "fit page to screen" thing which seemed to be shrinking images/fonts at different points. Also, keep in mind that if the screen DPI is set correctly by the X Server a 12pt font will be exactly the same size on your desktop, laptop, N800 and N900. That being said, I'm hoping there are plenty of options for selecting font sizes.

-John