I reccomend none... They will make your computer worse... All they do is keyword the registry and delete keys. They dont check for dependencies... So when an application runs it shows errors. I reccommend that you just leave the registry alone.
I found one that seems to be working pretty well for me. It's freeware too, so don't worry about subscribing. It's called RegSeeker. http://www.snapfiles.com/get/regseeker.html
You can also make backups before changing anything, so if you mess anything up you can just restore.
