Measuring common fonts for web design?

[eclipse]

Hi all,
is there a place that measures the most common fonts used on viewer's machines? I'm wondering how you all go about designing what you want in terms of type.

[angelwatt]

By examining study results like this. (http://www.codestyle.org/css/font-family/sampler-CombinedResults.shtml) There's a number of these web sites and easy to find by Google.