I’m always a bit dubious over Clean-up tools without in depth knowledge how do you really know they’ve done their job? Of all these tools CCleaner seems the best of the bunch, for instance Web User awards the tool 5 out of 5 stars and PC Pro makes CCleaner its “software of the year” for 2008. I’ve used the tool and it certainly finds a bunch of errors in my registry. Be-aware, that it can be a little over enthusiastic in cleaning Windows (Vista in my case) removing recent document history and cookies that you might wish to keep, however you can tune CCleaner to keep these files, just remember to configure it before using.