You can configure your machine for a network or dial-up connection in one dialogue box instead of several. Sharing folders within workgroups is dead easy. With Cocoa and Carbon being the principal two tiers of the MacOSX environment, the third is called Classic. This is effectively MacOS 9.1 running on top of MacOSX, letting you run all your existing applications. Classic mode can be launched and quit as required throughout the day without restarting your machine, and it actually works very well indeed.
Classic programs run happily, although looking very different, alongside native programs.
You can't drag and drop between them, but you can cut and paste, and share documents and folders. A dual-boot system is built into both MacOS 9.1 and X, so you can choose to restart in the former only, if you're having problems with certain devices. Since MacOSX-native device drivers are currently as easy to find as hen's teeth, this is just as well. This is actually a major issue, when you think about it. If you try to run MacOSX on any less memory than this, your hard disk will be churning constantly.