I've received today the same question from friends: is it possible to upgrade my Windows XP machine to Windows Vista? Obviously... YES! But is it a good choice or it's better to start from a clean machine?
I'm seeing that it's the first thing that makes people worried: too many times people doesn't go with Windows Vista because their machines have Windows XP installed (with lots of custom applications) and they're worried to loose al their data and (expecially) that the upgrade process to Vista will create a "dirty" installation.
This is a false myth now... Windows Vista has a completely new upgrade process that permits you to start the OS as a new installation and then restoring all your previously settings.
The Windows Client Team has explained this new feature in the past:
"Upgrade to Windows Vista are no longer a 'merge' with the old OS. First, Windows Vista's setup gathers old OS settings and user settings and data and stores them. Then it wipes away the old OS and applies the new operating system image (which is really fast thanks to Image Based Setup). Next, setup applies stored settings and data to this clean install based on per-component logic in manifests and plug-ins, which magically brings back your applications and data in a brand new OS. Your registry and file system are free of goo that is no longer needed by Windows Vista.".
So, don't be worried guys... if you want to embrace the Vista world, upgrade your Windows XP machine... 