A few more programs that I use that I didn't see on the list were
Advanced Windows Care - This program scans for viruses, defrags your hard drive and has plenty more features. It is a free program but it does have a payed version as well. The biggest difference that I've seen is that the free version does not automatically defrag your hard drive in the background where the payed version does.
CCleaner - This is a registry cleaner
Easy Cleaner - Another registry cleaner