I've had reason be grateful to sys restore in the past. Althugh I agree, it is a blunt instrument. Off is no trouble, provided you remember to set restore points either a) from time to time, or b) before you shoehorn in some unwieldy piece of software, unsure fo the outcome on the system.
One of the beauties of windows 7 is the fact that I can try stuff out on it, prior to dumping it on my main build, with an approximate idea of whether or not to go ahead.
Of course, another approach is to take an image on a regular basis. My Acronis is just about to launch on it's weekly image, that has saved the day a couple of times too.