I use Monster Cables Signiture Series Voltage Regulator and a Panamax 1000 surge protector, with the Monster S.S. 7000 surge protector on its way to replace the panamax. The better protectors should also clean the power so you don't get interferance with microwaves, mixers or other small appliances.
As far as do they work I guess I just look at it as cheap insurance, in case of a lightning strike.