You can keep your Brandywines and Marvel Stripes, delicious though they are. When it comes to summer heirloom tomatoes, I head straight for one thing: The Black Krim, photographed above in my back yard with no photo enhancing. Just the pure ruby-fleshed deliciousness, shining on through!
Here in the Bay Area, several farmers must feel the same way I do because the Black Krim (and its kin the Black Zebra, Black Cherokee, etc) are pretty easy to find in many famers' markets come tomato season. And no wonder, for these fruits are consistently perfect in all the ways I want my tomato to be perfect. With a juicy yet firm texture and nicely balanced in sweet and tart, this tomato is rich and robustly flavored. A winner all around.
Appearance always comes last in my assessment of a food's worthiness, but in this case, the astonishingly deep red color of a 'black' tomato is also a plus. It's true that we eat with our eyes as well as our mouths. Still, that deep color, which sometimes can look brownish with occasional streaks of green, has kept this tomato from commercial production. (More conventional farmers feel its odd appearance will keep it from selling well in the supermarkets.) Whatever. I can't remember the last time I bought a tomato in a supermarket anyway!
Most black tomatoes originated from the Crimean peninsula in the Ukraine where hot summers encourage the development of sugars and darker, mahogany-hued pigments. Also delicious is the Black Cherry (exactly as it sounds, a deep ruby-fleshed cherry tomato) and Cherokee Purple. Here's an excellent listing of varieties of black tomatoes (with pictures!) from the wonderful people at Heirloom Tomato Plants.
Related: Tastes Like Summer: The Perfect Tomato Sandwich
(Image: Dana Velden)
How To Cook Fluffy, Tasty Quinoa
How To Make Classic Chicken Salad
Good Food to Share 
The Big Book of Small, Cool Spaces 
Apartment Therapy Presents 
The Eight-Step Home Cure 
Elizabeth Apron fro...
Before & After: Emily Henderson Transforms a Senior's Studio Space
Monica & Austin's Charming Bungalow
Black Krim is always part of my tomato collection. Great photograph!
And while the Crimean peninsula is where these black tomatoes originated, its their genetics (and human selection) that gives them this pigmentation.
Due to the fact I have a brown thumb and we rent, I do have to buy tomatoes at the supermarket from time to time. Especially in the winter months, when I'm having a craving for a BLT or other tomato focused meal, I'll use Kumatos, which are readily available where I shop. I'm not sure if they are considered Black Tomatoes, but they are definitely brownish-green, and are pretty damn good, all things considered.
Paul Robeson is my favourite!
Black Krim is my favorite, too. And right now my garden is full of them!
None of these ones compare to the new Indigo Rose that was bred at Oregon State University. The insides are red, but the skin is black-purple. About the same color as a dark purple eggplant! The small immature tomatoes start off looking like blueberries.
Are these GMO? I am leery of those I see in my supermarket.
I have black Russian Seaman heirlooms ripening on the vine right now, yum!
Agreed! Black Krim is a delicious tomato! And not GMO, @daleyden, heirloom. Another one I like and grew last season was Carbon. And I second the Paul Robeson- always a winner. Purple Russian is a black plum tomato, so good for sauces. "Black" tomatoes are definitely my favorite, followed closely by orange/golden tomatoes :)