In case you haven't yet used the popular and well-reviewed CCleaner, here's a thumbnail sketch: It deletes unneeded files, erases your browsing tracks, kills unwanted cookies, and kills unnecessary files associated with a variety of programs, including all popular browsers, Adobe Acrobat, Microsoft Office, and many others. It also includes a startup monitor, uninstaller, and other useful tools. (Related products from developer Piriform include defragger Defraggler, undelete program Recuva, and system info utility Speccy.)
CCEnhancer integrates directly into CCleaner, so much so that you may not even notice that CCEnhancer is running. It gives CCleaner the ability to clean the traces of more applications than CCleaner can normally handle--dozens of them, including Microsoft Works, LogMeIn, Ashampoo Burning Studio, and many others. CCEnhancer puts asterisks next to any programs in the CCleaner list that it gives CCleaner the ability to clean. Check the box next to any program whose traces you want cleaned, and CCleaner will clean them, along with the programs it normally cleans.
You'll need to keep a few things in mind when running CCEnhancer. During the installation process, you'll almost certainly get a notice that the latest rules haven't been downloaded, so make sure to click Download Latest. If the rules don't download, add http://content.thewebatom.net/ and CCEnhancer.exe to your firewall and anti-virus ignore list. You may also have to run the program as an administrator in Windows Vista and Windows 7. I didn't have to do so on my 32-bit test system running Windows Vista, but installation instructions say that you need to.
Once you do that, though, you're ready to go. Anyone who uses CCleaner should use CCEnhancer: You get more cleaning with no more effort. If only the same could be said about cleaning one's house.