Would it be nice when you can schedule the cleaning operation of CCleaner??? I guess this is one important feature missing in CCleaner that are widely available in other software of this category. You can then choose an option what type of cleaning you want or if you want to clean the registry as well, then if you want a prompt to show in case you want to backup the registry keys.
I also notice that CCleaner has to clean the area of the registry where useless reference to removable disk drives and CD's are kept. Would be a nice feature too.