If you are still running Windows XP (yes there are still people running it) and you want to take advantage of the new 3TB hard drives up until now you would have been out of luck. Fortunately Paragon have stepped up with software software to enable this, and even better, its free!
If you need to upgrade from Windows XP to Windows 7 then you probably know there is no upgrade path - only a clean install. Have you thought about using the Windows Easy Transfer tool to help migrate your files and settings?
I'm going to build a new Windows 7 installation for my home workstation in a VirtualBox setup, so that I can continue to use Windows Vista, with (almost) no downtime.