With Windows source code being leaked to the public, this may well be the beginning of the end. Now that virus writers can see into the guts of the OS, finding vulnerabilities no longer requires guesswork. All they have to do is read the code. Soon we could find ourselves facing such horrors as jpegs on websites that instruct our computers to reformat their hard drives and spyware that can read our minds. What are we to do? Perhaps the time has come to familiarize ourselves with alternative operating systems.
In order to see what it's like to use OSX, just download MobyDock. It won't emulate the OS, but it will give you the doc.
If you want to learn about Linux, check out Knoppix. Go there and download the program. Then burn it as an image to a CD. Whenever you want to play with Linux, just boot from the CD. When you're done, take out the CD and your computer will boot back into windows, leaving all files, programs, and settings exactly as you left them. You can also do this with Phlak, but it doesn't have a Dvorak keyboard option, so unless your still using QWERTY, you're pretty much out of luck.
But if you're really serious about security, see if you can get your hands on one of these puppies. This is one of the greatest computers ever made and is completely impervious to viruses. You can even download an emulator. You can't beat that with a baseball bat!