CCleaner | Defraggler | Malwarebytes | SuperAntiSpyware | AVG Free | MyWOT
CNET editors gave the application a rating of 5/5 stars, calling it a 'must-have tool'. It was awarded Editor's Choice Award in April 2009 by CNET. As of January 2014, it has been the most popular software on FileHippo for more than a year, and also has a 5-star editor's rating on Softpedia.
Piriform announced in fall 2015 that CCleaner has been downloaded a BILLION times.