I've been using "DejaVu Sans", "Bitstream Vera Sans", "Verdana", Arial, Helvetica, sans-serif as my list. Seems to do what I want.
OSX users are such a small minority, its hard to find a way to please them without making it worse for Windows and Linux.
That, and I've viewed my website in Safari on OSX, it looks correct (although, like everything on OSX, it has hard to read fuzzy fonts).
There are many more OSX users than Linux on the desktop.
http://www.netmarketshare.com/os-market-share.aspx?qprid=9