Interesting article on Tannat, as linked in WineTerroirist, by Julia Harding:
in which we learn that the variety Tannat reflects terroir more than any other grape (ohhh...I thought that was Riesling...err...Nebbiolo..err..PinotNoir). Gets a little geeky in the discussion of clones. And focuses on Madiran and Uruguay, of course.
I've always thought the TablasCreek Tannat was one of the best. The Rockwall is also pretty good. I find many of the Madrians a bit on the rustic side. And not a big fan of the SouthAmerican versions.
But an interesting read, I thought.