I installed a set of two tone katzkins in my 07 Sierra about 6 months ago and I have been extremely pleased with them. It is somewhat of a pain to do yourself because you need to take the seats out of the truck and remove the cloth covers before you put the leather on but if you are somewhat handy you can save a lot of money by doing it yourself. I got mine from a group buy on gmfullsize.com but you can also get them here. http://www.jpcustoms.com/store/customer/home.php?cat=770
The kits come with everything you need for your specific interior including headrests and center consoles. I personally think that mine came out much nicer than the stock leather from GM.