FYI, OEM pads on these trucks are ceramic. Lots of fluff floating around on this thread...some vehicles do benefit from upgraded brake components, the Tahoe and 1500 series trucks included. The GM HD trucks have excellent brakes and there's really nothing on the market better than the OEM stuff.
What the OP needs to look at more than the pads/rotors are the LINES...GM trucks from this era are known to have uncoated steel brake lines that rust out. I changed my lines to stainless and went to braided stainless hoses as well.