And please tell me there is a way to disable this automatic updating crap. I have never in my life been happy that something automatically updated itself. On this machine (my Windows 7 laptop) all automatic updates for all software (except Avast) are disabled, and I've been very happy with that. (Nevermind the hardware nonsense that I'm not happy with - I don't like automatic updates.)
Control Panel -> Windows Update -> Change Settings (Sidebar) -> Important Updates
That said keep in mind that the
vast majority of updates are literally doing nothing but fixing security holes in your programs. Lots of people forget this, but the updates are there to protect you in almost all cases. As an example the last Java patch contained nothing except patches for over 98 possible ways that people could use to break into your computer (and that there were at least some documented cases of them already being used). Windows security updates are the same, and checking my current list of updates my computer needs to install I've got at least 14 unpatched security holes, and probably many more than that.
Personally my advice is this. Go to that setting and change it to "download updates but let me choose whether to install them" (the "you must restart in 10 minutes" popups will still show up rarely, but they won't ever actually count down and you can just close them). Then when you are sure you are done with the computer at night just hit the "restart and install updates" button and let it run. Wake up in the morning and your updates should be installed without any real hassle on your part, keeping both you happy and productive, and your computer safe from security exploits.
As for how long updates take, sometimes updates can be over 60 MB of just patches. This can take a while, especially if they involve the parts of the computer that it's currently using to install said updates (since you basically need to make a copy to keep the updates installing, then change the old copy, then go back and test if it works, etc.). In general I suggest not turning the computer off in the middle of updates unless you are 100% sure it's stuck (as in, you went to bed and when you woke up it's still stuck). Turning it off during the wrong time can seriously mess up your computer, and if you are unlucky there won't be much you can do to fix it but totally wiping it and reinstalling windows (I hope your backups are up to date!).