Run Windows and Mac OS Both at Once - New York Times: "Suppose you're finishing a brochure on your Mac, and you need a phone number from your company's Microsoft Access database. You double-click the Parallels icon, and 15 seconds later -- yes, 15 seconds -- Windows XP is running in a window of its own, just as you left it. You open Access, look up and copy the contact information, click back into your Mac design program, and paste. Sweet.
Using Boot Camp, you'd restart the computer in Windows, look up the number -- but then what? Without the ability to copy and paste, what would you do with the phone number once you found it? Write it on an envelope? "