I found several great tips for my recent first visit to Spain on this board - thanks, Chowhound! So I figured I would share some experiences.
Ate and drank at several wonderful tapas bars in the Santa Ana/Huertas area.
-El Lacón (c/Mauel Fernandez y Gonzalez) served the best pulpo - seared and sprinkled with paprika - I've ever tasted, along with yummy pimientos al padron. Returned for a delicious lunch - everything on the menu del dia was great, including a whole roasted fish and a bean soup flavored with bits of orejas.
-Casa del Abuelo (c/Victoria 12) specializes in fantastic gambas al ajillo and a sweet but yummy house red wine (the only drink served).
-Across the street at La Oreja de Oro (c/Victoria 9), yummy mushrooms and a plate of delicious ears.
-My favorite place of all was the sherry bar La Venencia on c/Echegaray. (Special thanks to the Chowhounder who posted this tip!) A modest and altogether perfect bar: delicious sherry (especially the amontillado); only the essential edibles (cheese, sausage, ham, mojama - my first time trying this air-dried tuna loin, it's fantastic with sherry); a diverse, friendly, highly watchable crowd; amazingly efficient bartenders; decor consisting of smoke-darkened sherry posters and a few presumably vintage photos of the bar looking exactly the same as it does today.
Outside of Santa Ana, a few places I enjoyed included Plateria, across from the Prado; Estay, a cafe-bar in tony Salamanca (c/Hermosilla 46) with great nibbles (especially tortilla with bacalao), wine and upscale people-watching; and Taberna Angel Sierra, an old, bustling, atmospheric vermouth bar on Plaza Chueca.
Hosteria del Laurel in Plaza de los Venerables in the Santa Cruz neighborhood had a wonderful tapas bar. (I never ate at the adjoining restaurant, but in fact stayed in the hotel above it, which was a good value and ever so convenient.) Highlights included octopus salad, tripe and the sweet "exquisite orange wine" advertised on the wall. Many of the other tapas bars in the Santa Cruz area were also great; further north, I enjoyed Bar Alfalfa off of Plaza Alfafa, which looked like a hopping chowhoundy area.
Several of the tapas bar just off Plaza Nueva were tasty and atmospheric, including Bar Castañeda and Bar Castellano, the latter of which served up a fantastic tabla of meats and cheeses. After a promenade down c/Reyes Catolicos (where the entire population seemed to be strutting its stuff on Saturday night), Los Manueles (c/Zaragoza 2, off Reyes Catolicos), a cavernous tapas bar and restaurant, hit the spot with riñones and roasted bits of ham with garlic.
It was the off-season, to be sure (early December), but it seemed near-impossible to get a bad meal in Spain. Thanks again to Chowhound - and all the bartenders, waiters and cooks!