My main reason of creating partitions is bescause I can format one without affecting the others
An Image tool (for example Ghost, DriveImage or others) makes a copy of your harddrive/partition or any folder. You can choose to compress it. The copy can be restored later.
Lately I installed WindowsXP Pro on the first partition, downloaded and installed all updates, and made an Image of that partition and stored it on another partition.
If something happens to my system, all I have to do is resore the Image to the Partition I want Windows to be. Ofcourse all files of that partition will be deleted because it replaces all data.
You could install Windows and a lot of programs on the same partition and make an Image...this way you never have to install Windows and all these programs again...you simply restore the Image you stored on another partiton to the Windows partition and a clean windows including all previously programs is ready for use.
I love partitions!! Just format c: and all my documents on d:\ are preserved