I'm not going to spend too much time on this topic, but I wanted to point out that just because a certain Mac model or a certain third-party peripheral/accessory isn't "officially" supported by Apple, doesn't mean your computer is relegated to the scrap heap. Third-party developers have provided some novel solutions that let you use Mac OS X on unsupported hardware, and peripherals that aren't officially supported by Apple or the peripheral's manufacturer. Here are a few examples:
XPostFacto A freeware solution that allows you to install Mac OS X on a number of unsupported Macs. For instructions, downloads, and a list of Macs that are compatible with XPostFacto, go to http://eshop.macsales.com/OSXCenter/XPostFacto/.
Sonnet PCI X Installer A commercial product from Sonnet Technologies that allows you to install Mac OS X on many computers that have been upgraded with Sonnet processor upgrade cards. For a list of supported computers and processor cards, visit http://www.sonnettech.com/downloads/osx_upgrade_sw.html.
USB Overdrive X Although you can connect any USB pointing device to your Mac's USB port, most devices require some kind of driver in order to function properly. Unfortunately, some USB peripheral manufacturers haven't provided drivers for Mac OS X. USB Overdrive X is a shareware driver that works with almost any USB pointing device, allowing you to use mice, trackballs, joysticks, gamepads, etc., that don't currently have drivers. See http://www.usboverdrive.com/.
Gimp-Print Although Mac OS X includes drivers for many printers, many other printers, including some very popular older printers, aren't currently supported. However, you can take advantage of Mac OS X's open source printing subsystem to provide printer drivers for a wide range of printers. I actually discuss the Gimp-Print drivers in depth in Chapter 12. See http://gimp-print.sourceforge.net/.
SWIM 3 Floppy Driver If you have an early beige G3 Mac or a PowerBook G3 Series that came with a floppy disk drive, you're surely aware by now that the floppy drive is not supported by OS X. The SWIM 3 driver allows you to use the floppy drive under OS X. Note that this driver only works with pre-installed floppy drives; it doesn't work on third-party floppy drives. Visit http://www.darwin-development.org/floppy/.
Remember, "unsupported" means just that—if something goes wrong, Apple won't help you, nor will most other software vendors. So use these types of hacks at your own risk.