I would advise highly against shutting them off... They updadate windows; security fixes primarily (when I get bored I've actually read the blurb on each of them to see what they are, 90% of the time they're cleaning up old/exploitable code).
Where there are some that you could potentially skip, it's not advisable to disable it... Though that is an option too...
In windows 7 go to the blue orb in the bottom left corner, go to "all programs", then "windows update" from here click "change settings" and you get several options:
- Important Updates
--Install Updates automatically
--Download but let me choose when to install them (which I use and usually just click install before bed)
--Check for updates but let me choose when to download them
-- never check (turns windows updates off)
- Give me Recommended Updates the same way I recieve normal ones (basically allowing you to choose them when choosing what you want to install the normal ones.
- Allow all users of this computer to install updates (basically allowing non admin users to install updates)
- give me updates for new and optional microsoft updates (i think this allows you to get updates for office products too)
- Show me detailed notifications when new microsoft software is available (I have this off, I assume it just tags on more info about updates, but it's a relatively new option from another update).