Ccleaner and Advanced Windows care are both good. They are free and offer a general cleanup, over and above the registry. I use Advanced windows care with its defaults, fortnightly. It has done no harm so far.
I suppose it should be pointed out that it is rarely needed to clean the registry, unless you experience a major irritating problem. Unlocated items are ignored and the impact on improved performance, after using a cleaner, cannot even be measured.
So, you are going to ask, why do I use it? - Because I am a cleaning fanatic!!