Serious Eats - seriouseats.com

Guinness is an Irish Dry Stout. It style is very balanced between malt (sweetness) and hops (bitterness and spiciness). That said it appears that you haven't developed a taste for highly hopped beer. There are a whole range of balanced to malty beery styles out there. First I'd suggest any dark lager as they are all more malty than hoppy. Bock, Dopplebock, Marzen, Oktoberfest, Alt and Dortmunder are all good styles to explore for your taste preference. In the ale category try: brown, porter and cream/milk stouts. None of those styles are dominated by hops. You do not want: ESB, India Pale, Pale Ale, Imperial Stout, Barleywine or even some Trappist styles.

If you work with the above listed styles you are not likely to find a seriously hoppy porter as it doesn't fit the style guidelines.

One of my favs: Sam Smith's Oatmeal Stout

http://www.merchantduvin.com/pages/5_breweries/samsmith_oatmeal_stout.html

Beamish is an awesome beer - similar to Guinness, but a little sweeter and more chocolatey. Another favorite of mine is Shakespeare Stout - it even made 3Luxe's top three beers!

Link: http://www.3luxe.com/best_ofs/Beer/Shakespeare_Stout

Also, finding some local microbrews would be a good idea as well - and trying all the different beers is just fun! I know that most bars that carry a wide variety of beers in Chicago (where I live) have "tasting menus", where you can try two or three ounces of a bunch of different kinds of beer. It's a good way to sample new styles.

Beamish!

Old Rasputin Imperial Stout is my favorite stout. Black Flag Imperial Stout is supposed to be good as well, but I haven't had the chance to try it.

I don't know if they have it around you, but Yuengling makes a really nice Black & Tan and their Porter is quite good as well.