This is my favorite gelato combo - coffee, dark chocolate and coconut - from my favorite gelateria in Rome - Giorgiagel. It's a tiny outpost in Trastevere on via. S. Francesco a Ripa that you never read about. But after trying all the major, well-known gelaterie, this one could not be matched, at least for my benchmark flavor, dark chocolate - or "cioccolato fondente," as they say in Italy. It's wickedly good. Aside from the intensity of the flavor, you get the most for your euro here - this cup or "coppetta" cost only 1 euro - or the equivalent of about $1.40 during my trip. And they add a crunchy cookie.
Giolitti, one of Rome's beloved institutions, is my second favorite gelato spot in Rome. The coconut flavor here is the best I've tasted anywhere, with flecks of fresh coconut adding texture and more taste to an already yummy flavor. The coffee is really intense too, but the dark chocolate doesn't hold a candle to Giorgiagel. The flavors on display in the case are myriad, with a rainbow of fruit sorbets including mango, plum and wild berries. This heaping cone cost 1.50 euro. Located at via Uffice del Vicario, 40, not far from the Pantheon.
Dark chocolate and caramel at San Crispino - another landmark gelateria in Rome with several locations - one near the Trevi Fountain and one near the Pantheon. Right off the bat, I don't like the fact that their ice cream is served from covered stainless steel containers, so you can't see what you're ordering. Moreover, the price of this meager serving is double - 2 euros - what I paid for a heaping cup at Giorgiagel, and the dark chocolate is much less intense.
To round out my tasting, (I had to give flavors other than chocolate a shot after all) I include photos of two other combos - a luscious amarena (sour cherry) and frutti di bosco (wild berries) -- and a cup of torroncino (nougat candy) and pistachio. Both from Giorgiagel, and 1 euro each.
I totally agree with your assessment of Giorgiagel. We've been living in Trastevere for the past nine months and stop here with our daughter several times a week...it is by far the best gelato we've found in Rome, especially when you consider taste, price and unpretentious friendliness of the owners and staff. The gelato there is wonderful and deserves to be better known...since they have only been open a couple years, I am sure they will soon get the reputation they deserve....and I also agree with all you said about San Crispino...over-priced and too pretentious for my taste-buds...