Some people (ie. MedinaSoft) likes to have personal folders, such as "My Documents", on different drives instead of the default "C:\Users\Username\Documents".
- Open up your current "My Documents" folder in Windows Explorer
- Right click the folder
- Properties
- Select the "Locations" tab
- Click "Move"
- (Create) and select the folder you want as the new location for "My Documents"
- Click "Apply"
- Click "Yes"
- Pop bottles and models.
Also, remember to update your "Documents" library once you've relocated the folder.
*edit*
14/09/2009 - You can also do this for a bunch of other folders in your "Users" profile, like "My Music" and even "Desktop". It all works in the same way.