If you are starting from a bare metal install, you can slipstream updates into your installer disc so it already has updates in it (this depends on how many installs you're doing to make it worth it).
WSUS will not reboot your computer for you. It only keeps track of your updates and will act as a repo for updates so that rather than updating 300+ meg of updates from your Internet connection, they'll come from the local network. It can also control which systems get updates (I want to update IE for all the computers in HR, but restrict it from Marketing...) and give you reports on what updates your systems in the network have. The update mechanism sucks in terms of giving feedback of what is happening, but that's a shortcoming of Windows Updates. It also won't prevent the constant "You're updated! No, wait, you're not..." reboot cycles. Through group policy, you can have the system update with Windows Updates automatically on a scheduled basis just like regular Windows can be set to do individually if you don't mind becoming fully updated over a few days and leaving it on overnight to regularly check for updates and reboot.
Another method is to use the Windows Deployment Services (if you have, say, a lab of systems to update.) You take one of the systems, fully update and configure it, then sysprep it and upload that to the WDS server. Then netboot the subsequent systems and install the full image, fully updated. You have a lot of time invested in the first system but save time when you have 30 systems to install straight from the WDS server. Even if you don't create and auto-deployment script to finish the post-sysprep state you'll save a lot of time not having to do service packs, MS Office, custom installed software, etc. plus you can re-deploy the image when a system gets screwed up.
Otherwise you will have to do the updates repeatedly by hand, which as you've found, takes quite a bit of time. But at least you know that it was done without issues or errors.