I'd hate to think exactly how many times I've installed some version of Windows 7 since its debut back at Microsoft PDC 2008. There was the Windows 7 pre-public beta (that didn't have the new UI and menu bar), the Windows 7 public beta, the Windows 7 RC and the Windows 7 RTM. On my daily use laptop alone I've installed each of these Windows 7 versions, some more than twice. Then there's all the Windows 7 installations I've done under Hyper-V and on test machines prior to using them myself. So let's conservatively say I've probably installed Windows 7 at least 8 or 10 times (but it's probably more like 15 or 20.)

Now Microsoft is saying it can take anywhere from a half hour to 20 hours to install a fresh copy or do an upgrade in place, respectively. If you are upgrading from XP, well, you've probably got the longest road ahead of you and frankly would probably be better of doing a fresh install in my opinion anyway. When I can, I'll go the fresh install route most times.

There are ways you can make the fresh install time shorter, particularly when it comes to getting all your apps and configurations in place. The most important to do is keep all of your data on a separate partition (or drive) from the Windows OS. I mean put EVERY BIT OF YOUR DATA on a separate partition, including your Documents folder, Downloads, Outlook PST and OST files, favorites, music files, videos, pictures... all of the folders normally under my documents. If you were to drill down into my user folder on the C drive of Windows 7, you'd find all of those folders (Downloads, My Documents, My Pictures, et