Founders Breakfast Stout
Terrapin Coffee Oatmeal Imperial Stout
Highland Imperial Black Mocha Stout
Great Lakes Blackout Stout (possibly the best I've tasted, but each one has a different attribute that I could argue for)
Young's makes a double chocolate that's pretty common and good
Samuel Adams Cream Stout
Everyone of those trumps Guinness. I have had others that I can't think of off the top of my head along with friends breakfast stout home brews that also trump Guinness. I still do enjoy a Guinness from time to time, especially if we are doing Irish Car Bombs.