The standard super Unicode font from Apple is Lucida Grande, but now a version will be available to Windows users if they download the Windows version of Safari 3.
See http://www.alanwood.net/unicode/fonts.html#lucidagrande
Like the release of Microsoft’s release Arial Unicode MS for Mac OS 10.5 (Leopard) I think this is really good for the Web community. A lot of Mac-oriented designers have gotten hooked on Lucida Grande, but they don’t always realize that it’s not available on Windows (or they think that Arial is a good substitute, when Arial Unicode may be more appropriate.
With both Arial Unicode and Lucida Grande available for both platforms, the headaches of developing cross-OS friendly sites should be reduced in the future. We may be able to (gasp) pick a Unicode font we like and assume it will be on almost all machines. Wow!!!
FYI – If your site needs to display a lot of quirky characters (like this one does), I would still recommend your CSS file allow for both Arial Unicode MS and Lucida Grande…at least for the next few years.