A newer version of CCleaner is available.Or, Learn More About CCleaner
Full user review
"Make sure you know what you're cleaning out"
Lots of options gives a variety of ways to clean up your hard drive and improve its response time.
Multitude of options gives you lots of rope with which to hang yourself if you're not careful. For example, if there are cookies that you rely on, be sure to protect them before cleaning.
It's kind of like acid. Does a great job of eating a hole in things if that is what you want. You just have to handle it very carefully.