How about Kim Peek? He was the inspiration for RainMan

Or Rex Clack

Or Alonzo Clemons

Or Daniel

I think the most interesting thing about this is what you can learn about the qualities of artistic talents, how that develops, what it says about us as humans.

That is an example of Eidetic Memory, also known as Photographic Memory.

Before we get into that, consider that in the video they say that it takes the subject 7 days to draw the panorama. They don't say whether he was allowed outside to have another look or if he was monitored in his off time to make sure he didn't look at photographs, etc. They also don't show a comparison of his drawing (as remarkable as it is) and the actual skyline. So it is hard to have a useful opinion on his abilities with so many unknowns.

Anyway...

It seems that there is real controversy as to whether Eidetic Memory is a real trait or simply an application of learned behavior explainable by other means. Most tests have been inconclusive or have shown that there is nothing special going on.

The study that seems to crop up most in a cursory scan of popular literature is a 1970 test conducted by Harvard researcher Charles Stromeyer III on a student test subject named Elizabeth. This test seemed to demonstrate real eidetic ability in the test subject, but is not clinically convincing for many, because the test subject never repeated the test and to complicate things the scientist actually married the subject. ( from the "Kaavya Syndrome" publised at Slate, by Joshua Foer: http://www.slate.com/id/2140685/ and other sources. )

Cecil Adams in his Straight Dope column has an interesting summary of the issues around Eidetic Memory, that shows some people have demonstrated abilities which could be called Eidetic Memory, or could simply be mnemonic tricks: http://www.straightdope.com/columns/read/2350/is-there-such-a-thing-as-photographic-memory

Writer Anna Arnaudo at SerendipUpdate's Blog seems to think there is more evidence for Eidetic memory, but the whole subject is still unproven:

"Despite the numerous studies done to explore eidetic imagery, much is still unknown about this unique ability. Cases like Elizabeth and my own ability to visualize convince me that eidetic imagery is indeed possible. In reaching beyond this assertion, I found myself asking more questions after doing my research than before. The answers to these questions could provide fascinating information about the workings and the true abilities of the human brain. It already feels as if seeing people memorizing Russian vocabulary, a list of math equations or window arrangements on a large building does not seem like such a far stretch of the imagination anymore. Imagine the possibilities.
http://serendip.brynmawr.edu/exchange/node/1693

In his article "Kaavya Syndrome" at Slate, Joshua Foer is not convinced.
"This seems like as good an opportunity as any to clear up the greatest enduring myth about human memory. Lots of people claim to have a photographic memory, but nobody actually does. Nobody."

http://www.slate.com/id/2140685/

What seems to be a good scholarly bibliography can be found here:
http://pages.slc.edu/~ebj/memory04/questions-answers/photographic.htm

Naturally Wikipedia has lots to say:

http://en.wikipedia.org/wiki/Photographic_memory

Including a list of people who it is claimed have had this ability:
"A number of people claim to have eidetic memory, but until 2008, nearly no one had been tested and documented as having a memory that is truly photographic in a literal sense. Regardless, a number of individuals with extraordinary memory that have been labeled by some as eidetikers."

Some excerpts:
Napoleon Bird was an English barber in the 19th century
Tom Morton, a taxi driver, knew over 16,000 telephone numbers in Lancashire
Abbie Hoffman, the charismatic leader of the Yippie movement
Wolfgang Amadeus Mozart appeared to have a perfect musical memory
etc...