I use Revo Uninstaller quite often to uninstall things I don't use, as well as CCleaner. Virus scan everyday and don't download very often.
It really isn't necessary to use Revo Uninstaller unless no other method works for removing a program. I've heard of too many instances where Revo has removed more than necessary. If you are using the registry cleaner portion of CCleaner, that too isn't necessary with Windows 7 unless you are having a problem caused by a left-over registry entry. The reason is that Windows is a closed source system. Developers of registry cleaners do not have the core code of Windows 7 and are not working on definitive information, but rather they are going on past knowledge and experience. Automatic cleaners will usually have to do some guesswork.
Modifying registry keys incorrectly can cause Windows instability, or make Windows unbootable. No registry cleaner is completely safe and the potential is ever present to cause more problems than they claim to fix. Registry cleaners cannot distinguish between good and bad. If you run a registry cleaner, it will delete all those keys which are obsolete and sitting idle; but in reality, those keys may well be needed by some programs or windows at a later time.
Windows 7 is much more efficient at managing the registry than previous Windows versions. Even if you are very knowledgeable of the registry, the few keys left over when uninstalling programs will not make 1 millisecond's difference in performance.
Forget all the "wisdom" you learned about XP. Windows 7 is not XP and does not manage the registry the same as XP.