Are a pain. I work supporting a smaller retail retailer and have disabled as many auto-updaters as I can. The people working on these machines don't need to be bothered by balloon messages appearing in the notification area. It breaks their train of thought and disrupts the flow of dealing with the customer when they stop to read that Adobe Updater will now check for updates.
So, I've made the machines as lean as possible when it comes to applications - only what's needed to get the job done, and the those applications are updated weekly. No Itunes (really! the bosses were using the POS computers to load their iPods!), Real Player or Acrobat (Foxit works fine for what we do).
It bothers me that when I put in an updated version of an application the auto-updater gets re-enabled. I specifically disabled it, why can't my configuration settings be saved? Can't they ask me before assuming that I want it turned on?
They don't let you choose the time to update, unlike Windows update and anti-virus products. Maybe if they did, I would be more inclined to use them.
And yes, it is handy that Secunia has a tool for this. Funny how they managed to bring this to our attention. Nice of them, I guess.