Even though Mac OS X has been around for many years now, certain well-liked and eminently useful software apps never made the jump from Mac OS 9 to Mac OS X. Ever used Word Perfect for Mac? Version 3.5 was the last version, built for Mac OS 9. Who can forget Word 5.1, so capable and snappy, before Microsoft Office became the bloatware behemoth that is is today? How about Symantec's outlining word processor MORE 3.1, still arguably one of the best in its class, even after all these years? And then there are those legacy LEGO games...
It would be easy to go on and on about great software--some well-known, some fairly obscure but to those in their respective niches--but suffice to say that a good argument can be made to keep Mac OS 9 functionality around, at least for awhile longer, even if only for nostalgia.
So, for whatever reason--honest business need, opening those old MacDraw files, or just for grins--you want to run Mac OS 9, or even pre-OS 9, on your new Intel-based Mac. Apple says it can't be done, in fact their internal sales training on virtualization specifically states as much, but of course they're wrong. You can even run Mac OS 9 atop Windows and Linux, for crying out loud.
Visit http://www.emaculation.com/ to see the possibilities.
Perhaps you're more interested in a drag & drop solution? A guy called "gwalkabout" created created an easy install of SheepShaver called COI (Classic On Intel), but version 4.0.1 (aka chubby-bunny) was the last one. I upgraded that version with the latest version of SheepShaver and some useful Classic apps, and called it version 4.0.1+. You can download my version at COIV4.0.1+.zip --presuming you trust me. If not, your loss. :)
There you have it. A way to run Mac OS 9 on the latest and greatest Apple hardware. It will impress your friends, possibly astound the staff at the Apple Store, and it might just come in handy for some real work once in awhile. Who knows?