well you do have a point. in most cases service packs are bug fixes and
security updates.
so its always advisable to update to the latest one.
But dont do them at once. take a test machine or two which reflects you
organisations normal machines. And deploy the there. Test your application
to see if the fixes dont break anything. Yes sometimes it does if underlying
mechanism was changed or modified. As and when you and your Sys Admins are
satisfied... just release it for entire orgainsation.