I know I've seen people speccing up PC's and including either the gold or platinum warranty.
Personally I didn't and haven't had any issues, but problems can happen.
I have gotten a PC (as opposed to a laptop) and took out the platinum warranty (using a better safe than sorry approach) although are you talking about the PCS warranty or something else? Not had the PC for 1 year yet though.
I went for bog standard and have just had a GPU replacement 6 months from purchase, wish i'd at least gone silver as a minimum its £35 charge to get it back to them. My fault though.