It's worth mentioning at least for a lot of major titles, there is a Mac version available. In fact, there were some games where I think the Mac version predated the Dos version(Oregon Trail comes to mind).
Getting the native Mac version really is the best of all worlds.
With that said, I've had great luck with Dosbox for a lot of the old shareware/freeware games that I use to love playing. You could also run Win2K in VPC, which lets you cover a bunch of both DOS and Windows games.