The freeware CCleaner hasn't seen many major revisions since Piriform launched it in 2004, so when you do see a major update, you can be assured that it's going to come with impressive new tools. CCleaner 3 doesn't disappoint on that front, introducing two major new features that make it worth the upgrade.
One is a drive wiping tool that can wipe all the data from your hard drive, but can also scrub only the available free space. As with many of the tools in CCleaner, it's fairly nuanced and allows for a simple one-pass overwrite, a Department of Defense-level three-pass option, a National Security Administration-level seven-pass cleaning, and a 35-pass Gutmann-level deep scrub. The more passes you select, the slower the deletion process.