Some strange people like OmniWeb, (http://www.omnigroup.com/applications/omniweb/) I see no point when Apple's native browser does an excellent job and (of course) for free.
As for Media, Mac OSX comes with iTunes (and is available for OS9, to my knowledge) which plays music, some formats aren't natively supported, however can be added via the relevant libraries.
For video media, there's QuickTime which can play all your video's including DivX etc with the right codecs. For media that QuickTime can't play there's VLC which I mentioned in my last post, everyone that I know uses it. Also MPlayer is a nice VLC alternative (http://mplayerosx.sourceforge.net/)