I've been using calibri and corbel fonts for the web, because the older browsers that don't anti-alias the font under 16px show these (and a few others) show these anti-aliased.

one problem I found that these fonts are smaller than the standard pack. so usually adding a px or two is necessary, but if the font is not there, the alternatives are a bit big, so I embed for all major browsers, and these two fonts are going to be a lot more common in a few years as they are bundled with Vista,7, and the microsoft suite.

anyhownow, the problem I found is that firefox doesn't like the font bold for some strange reason. It renders it as bold at first, then it swaps to normal wight. It's strange, because if it couldn't find the bold variant in the ttf it shouldn't render it as bold in the first place.