Someone left a message in the comments of the blog recommending I talk about Ccleaner. Since I've always looking for topics, that seemed as good a one as any.
Ccleaner (originally called Crap Cleaner) is a utility that cleans up unnecessary files from your computer. This includes temporary Internet files, cookies, files in the recycle bin, and some unnecessary registry items. It will do a scan of your hard drive for the files and let you specify which ones you want to delete.
Note: Be careful when deleting registry entries. While I've never have had any problems deleting the software's suggestions, there is some potential that it could cause them.
Ccleaner is a nice way to make sure your hard drive isn't bogged down with useless items.