What's all that fuzz about dual booting!? Specially hyped in Apple's Mac notebook line. Dual-booting, the ability to boot a PC either into one (say Windows) or another (say Linux) operating system is most of the time a useless black or white proposition which reduces productivity dramatically. Because, yes you can boot into Linux when you want, but doing so means that you have to quit Windows... that means, suspend all things you or your desktop are doing, like downloading that wonderful movie, transcoding that two and a half hour movie to play in your portable multimedia brick, for example.
Let's cut to the bone, the ability to boot a pc into an alternative OS is most of the time just useful for emergency situations, let's say when some new driver update have stuck your Windows and prevent it to load until you use your installation disk (you have it, don't you?) to revert your system to a previously saved rescue point. If you have to do something in Windows right away and can't take the time to fuzz with system rescue, well, then just reboot your system into Linux and, if you have it set up properly, you could access your files and complete that urgent asignment. Just later you will take care of the comatose Windows.
If you insist on trying different operating systems by dual-booting between them daily, you will develop a double personality disorder much sooner than later.
What I recommend is that you use virtualization technology to test your target OS (say Linux) as a virtual machine running in your everyday desktop (say Windows). Then, there's no need to suspend any tasks in progress and shut down Windows, or even wait for the system to reboot; just click your Linux virtual machine shortcut in the Windows desktop and there your Linux boots, or resumes if you have previously suspended, preserving all opened programs, windows and documents you where using before closing the virtual machine.
Much better than that, once the virtual machine is properly configured, you can access shared files in one or another OS by just switching from the virtual machine windows to your Windows desktop, that simple!
Linux running in the virtual machine, given your computer is powerful enough (talk about this later), will perform and feel as if running on real hardware.
Of course, there are those once in a while situations where virtualization does not cut it and dual-booting shows its usefulness, like when you want to be shure that your real hardware is supported by your target OS, because a virtual machine runs on virtual hardware, which generally has different "virtual" specs than your real hardware. For example, you could configure a virtual machine to simulate being running on an Intel Celeron CPU, while your real digital brain is an AMD Athlon piece. Specially, dual-booting is almost inevitable if you want to check how does your target OS supports the advanced features of your graphics card, like 3D.