Ok, here we go, not sure what people will think of these, but anyway...
1. An option to securely delete the files and entries that ccleaner removes but writing over them with random data before they are deleted (possibility of letting the user choose how many times the entries are overwritten).
2. An option to automatically run ccleaner when windows shuts down or starts up, or when a specific programme is closed.
Both of these have been requested multiple times, and both are excellent features. Good suggestions, lets hope they make it into one of the new versions!
Don't sweat it! I've posted suggestions and later on seen that they were already there. It's good when other people ask for the same feature, because then it has more chance of actually being implemented.