Windows Update

that's done to desktops here, but we security guys keep that shit away from our gear.

THIS

Although we just purchased Patch Authority Ultimate from Scriptlogic to manage patching servers. Yay, no more manual stuff! Patches and then will reboot during the maintenance window.
 
my company develops and uses proprietary software to roll out security updates and everything else.

it was buggy and sucked at first, but now it works extremely well... does windows updates twice a month unless something is critical, rolls out it's own security updates from time to time. if you're update client is 2 revisions out of date, you can't login to the network. it's actually considered a hardened OS.