When I see questions like this, I say, "Go look on Google," you can get updates easily from W3C and places like that. The "safety" of fonts on the web has more to do (as you know) with what operating systems out there are preloaded with which fonts.
So look for two sets of data: what OSes are most prevalent and what fonts are preloaded onto them.
I've run across a table of just that information recently: http://www.codestyle.org/css/font-family/sampler-CombinedResults.shtml
Be careful, when you are looking, to check the date of the page you find. If it is earlier than today's date (February 2010), it's apt to be out of date.
You have to make your own decisions about fonts, use font-family lists, so that your most-desired font is first, next-acceptables are next, and generic (serif or sans-serif) are last, so that SOMETHING shows up if your fancy font isn't on the viewer's system.
And even though Arial Narrow, Copperplate Gothic Light, and Gill Sans (I love Gill Sans) may be "acceptable", I sure don't have 'em on my system, so be careful in your choices.
What a nice link! Thanks for that...
Thanks to both of you. Will look into your links and hopefully come to a conclusion!