Interesting. I have an Apple update manager too, but it operates differently. Seems to fire off periodically on a schedule, and never in my memory on boot. Glad to be wrong if it means your computer's probably safe.

Ahh, the Holy Grail, a computer that's secure and has just the right amount of crap on it. Goldilocks in a hazmat suit.

Doesn't exist, but not because a lot of people haven't sighed/screamed and wished for the same thing. But the response has always been to create sealed "appliances" like the iPhone. Appliances work smoother than general purpose devices like computers, but the necessary price you pay is to give up flexibility and the power to bend the machine to your own will. With an iPhone or iPad, all you can ever do with it is what Apple allows you to download from their App Store.

A PC is a damn sloppy thing. But personally I'll take sloppy but powerful over simple yet neutered any day.