Windows only: The biggest annoyance that comes with a reboot isn't the time wasted rebooting — it's the time wasted getting your workspace back up and running how you had it before you restarted. Free application Cache My Work fixes this problem.
Once installed, you can set up Cache My Work to monitor all "cacheable programs". (It's really just a checklist of all the open applications you're running.) Check all the apps you want it to monitor, including Explorer windows, and once you do actually restart, Cache My Work will attempt to restore your apps to where you left them — or as close as it can get to that point. Really it's just going to relaunch those saved applications; those with some sort of session restore capabilities (like Firefox, for example), should be back to where they were. Others will just be reopened.
Either way, it seems like a good app to have running every time Patch Tuesday rolls around. Cache My Work is a free, open-source application, Windows only.