You don't need to choose either a Windows machine or a Mac--although you cannot (legally, or reasonably) run Mac OS X on a Windows computer, you can easily run Windows on a Mac. You have several choices, but they boil down to two basic concepts: You can either dual-boot your computer, so you choose at the time you start the computer whether you want to run Mac OS X or Windows; or you can run Windows as a virtual machine while you're running Mac OS X. Both techniques have their advantages--I tend to run Windows as a virtual machine, using the excellent Parallels software (http://www.parallels.com). This software allows you to run Windows, and any Windows application, in a window while running your normal Mac software. It allows you to use your favorite Windows applications side-by-side with your Mac applications. In other words, you get the best of both worlds. For both scenarios, you'll need a licensed copy of Windows, but running Windows in a window, as a virtual machine, on OS X Lion on an 11" MacBook Air works perfectly for me. Check out Parallels (or its competitors, VMWare Fusion or VirtualBox) to see how easy it is to run Windows on a Mac.
Listen to the radio audio.