Question: If I use my second hard drive for data, will it make a noticeable speed increase in everyday computer use? Do I need to do anything besides moving my documents to the partition on the second drive? Should I also move my program files to the second hard drive?
Answer: Moving data from one drive to another should result in at least a slight speed increase since you are sharing the load at least a little between the separate drives.
Moving the data is relatively simple since you just need to move the files themselves. I have pages on how to get Microsoft Word to automatically save to the new drive and how to actually transfer the entire "My Documents" folder to the new drive.
Moving your application programs involves more work since there will be a number of references in the registry that need changing as well. Unless you have a program designed for moving software between drives it would probably be easier to uninstall and reinstall any software that you decide to move.
Another benefit in having your data on a separate drive is that it makes backing up the computer easier. With your operating system and applications you will either have the original disks from when you purchased the programs or will have downloaded a file that had to be run to install the program. Where you have the disks the program or operating system can be restored simply by reinstalling it. If the download files are kept in a download folder on your data drive then they can be reinstalled from there. The only thing on the system drive you'd need to consider backing up would be the registry - although that would be reconstructed by reinstalling all the applications.
Everything that you need to make backup copies of would be on the data drive and the backup process could be kept relatively simple by simply backing up that entire drive.