To plaintiger:

Actually, your settings would also have the problem of going to sleep inappropriately. Where this is most annoying is when watching a video in something like RealPlayer, Windows Media Player or some other non-Apple player. They don't disable the screensaver like Quicktime Player & DVD Player do, so 5 or 10 or 15 minutes into what you are watching, it goes blank. VERY annoying.

It's a great little utility that does exactly what it's supposed to. I'm glad someone thought to do it!