Hardware & internal SOUNDCARD PC & MAC compatible

Hi there,

I'm planning to buy a new soundcard so I came here to get some advices. My preference would go to a Vista 64 bits AND MAC OS Leopard  compatible, PCI Express if possible (but can also be PCI), with incomparable sound quality (like my creamware) & performance. My old creamware does not support 64bits OS and I want to switch from XP to Vista X64 before switching again to Windows 7 wich is really damned fast and stable, even for a beta version. It must be also Mac OS compatible as I'll also install a Hackos Leopard on my PC :-p Any ideas, good tips ? Price does not really matter. Thanks !