Lucida Grande is the Mac OS X default font. As with all things OS X, it is absolutely stunning, in all its anti-aliased glory. It goes perfect with Mosfet Liquid in KDE, and with the IceMan OSX theme in Windows XP. A font for all occasions.

It can be compared to Verdana, but thinner and slightly taller. You can download this font, along with Apple Garamond (The font that Apple uses for its ads and such-the tall serif one) at http://www.jonmega.com/~iceman/stuff/fonts/.