In Windows Vista and 7 you can easily relocate the various folders associated with your user profile to your Hard drive. Here is how:
1. Click on the Windows button and click on your user name (should be just below your account picture in the upper-right corner of the start menu). Alternatively, go to C:\Users\<username>
2. Right-click on the folder you want to relocate, like the My Documents folder and click Properties
3. Select the Location tab and on the Location tab, click the Move button.
4. Browse to a folder on your hard drive, like D:\Users\<username>\My Documents
5. Click Ok. Windows will ask you if you want to move all the content to the new location. Say yes and repeat the above for any remaining folders.
Now your Desktop, documents, music, pictures, etc will all be located on your HDD instead of your SSD, and any time you save something to the desktop, for example, it will be on your HDD.
You can do this on a much wider scale for all users on a computer (or all domain attached computers) using Group Policy, but that is probably overkill. If you're interested, take a look here:
http://technet.microsoft.com/en-us/library/cc732275.aspx
--Russel