Every user has their own font folder in which to place fonts. MacOS X gladly uses standard MacOS Classic TrueType fonts without any conversion. J ason Sears asked a very interesting question regarding MacOS X and long file names. There is no information yet on Apple's site, but this is what I discovered with a little experimentation.
X supports long file names.
Very long - up to 255 characters, but only the first 150 are visible on the desktop when an icon text box is selected. When an icon is not selected, only the first 18 characters of a name are visible. Only 31 characters are displayed and the truncated characters from MacOS X are converted to some form that eludes me. I imagine that after the release of MacOS X, Apple will post a TIL outlining these changes. The strange letters at the end of truncated long filenames from Mac OS X correspond to the file's or folder's reference number in the directory, converted to hexadecimal so that it uses up fewer filename characters.