I have Advance Task Killer installer to close apps to keep my Motorola Droid from running slow. I open the app and apps I have not used are running according to ATK. I have all the apps checked, I hit "kill selected apps". The app closes. I open the app again immediately and there will be a couple of apps running. I repeat the process and hit "kill selected apps" and still I will have a few different apps running. What is going on?
Which apps continue to crop up? You might be trying to kill some that are tied into the OS and always need to run (i think corporate calendar and a few other random ones are like this).
Any apps that start up on their own are doing so for a reason. Add them to the exclude list and there is a good reason to use a task killer. Don't exclude them and you are actually slowing down the system while it restarts those.