KySOn
This simple program provides a notification tray icon which can be toggled to either keep the computer screen on or use the standard sleep settings. It basically saves you the trouble of navigating to the power settings and switching between no screen timeout and 1 minute, if that is something you do frequently.
In case you are wondering why anyone would have that problem, here's my user story: I want the screen to stay lit when reading something, but I generally prefer to have it turn off after a short time when I am doing anything else: It is my firm belief that it saves me a lot of power (and money).
Since saving power was the original point, Kyson has two additional options: By default, it will stop keeping the screen lit once the machine is locked, and it will also just turn the display off immediately when that happens.