CodeWeavers CrossOver is a commercial product that lets you run specific Windows applications in Linux. It's an interesting strategy: It isn't a full Windows emulator, and doesn't claim support for all Windows software. And you must still own the applications you want to run (it doesn't replace or emulate the applications). But it supports MS Office 97 and 2000, Internet Explorer, as well as a bunch of others. If MS Office and/or IE are the only reasons you keep Windows around, you can get the best of both worlds and make the switch with this $55 product.