While I don't agree with many of the doctrines that Westom used to prescribe to, one thing I will agree with is that the VAST majority of surge protectors are worthless. What I don't agree with is his pennies on the dollar thing. If you have a good unit, and by good I mean something made by a well respected manufacturer like Tripp-Lite, Leviton or Eaton, then it's worth having. If you paid ten bucks for it at walmart or less at the dollar store, or if it's made by Monster or Belkin or a similar flavor of the month brand, it's probably worthless except as a power strip.
A false sense of security is all that is provided by the majority of "surge protectors". A good quality PSU, good quality surge protector and a breaker on that circuit at the panel are what you should have IMO. But, my opinion my not coincide with that of others, so be that as it may.
And also, as SS said, it's additionally pretty much worthless except in high energy events and that means a direct short to the external circuit or a lightning strike, both of which are on the wall side of the PSU. Surge protectors, as far as I'm aware, don't protect against excessive current draw from a direct short or other issue on the opposite (Motherboard) side of the power supply. That protection is supposed to be a part of the power supply. I suppose if the draw was big enough a surge protector might kick in, but since it takes very little to toast PC components, it would likely be far too late anyhow.