Remarkably, despite going back nearly a year on this board, I couldn't find a thread devoted exclusively to discussion of pintxos in San Sebastian. Our opportunity was limited to two nights (one spent in the Parte Vieja, the other in Barrio Gros) so our sample size was pretty small, but here's a quick recap of our experiences:
Bar Aralar - really just ducked in here to avoid the rain, and were pleased to find such a festive, colorful spread laid out on the bar. The tuna-stuffed piquillo pepper was nice, as was a plump artichoke wrapped in bacon. A pintxo topped with a vibrant greenish white seafood spread tasted mostly of pickles, and I couldn't make out what else was in it.Very much an old-school place - ask for a plate and report back on the honor system how many pintxos you took.
Gandarias Taberna - a warm pintxo of queso cabra wrapped with bacon was delicious; even better was one described as "milhojas de manitas y hongos", a layered concoction of shredded pigs' trotter meat and thin slivers of porcini mushroom. A brochette of cordero (lamb) was only OK, as was a pintxo topped with angulas (baby eels) and piquillo. They had a large selection of wines by the glass with all of them held in one of those high-tech Enomatic dispensers.
La Cepa - tortilla with bacalao, right out of the oven, was absolutely delicious. A little sampler of their chorizo was also excellent. The "gabilla," a croqueta type thing with big chunks of pork, serrano ham, and cheese, didn't do it for me. We should have taken the hint from the chorizo, as their specialty seems to be their Jabugo ham products.
La Cuchara de San Telmo - this place had been recommended by numerous sources and perhaps our expectations were too high, or perhaps we ordered poorly. More contemporary in approach, everything is made to order. A canelon de morcilla was pretty good, the pasta filled with a rich oozy blood sausage, and the dish brightened up with a stripe of an herbaceous green sauce. The problem I had was that pretty much everything we ordered had almost the exact same presentation. The foie with manzana brought a seared hunk of foie gras served over a bed of apple puree, with again the same stripe of green sauce; and then a duck breast (slightly overcooked and tough) came over a bed of orange puree, with yet again the same green stripe of sauce. Any one of them individually I would have thought were good, but when ordered together gave the impression of a one-trick pony. Again, maybe just a case of poor ordering.
Aloña Berri - perhaps in contast to La Cuchara de San Telmo, I thought Aloña Berri was absolutely everything it was cracked up to be. The "guiller" was a pintxo that came in an Asian soup spoon, one bite, more than a half-dozen components. From bottom to top, a puddle of creamy confited bacalao, topped with a smooth eggplant puree, hollandaise sauce, quail egg, aioli, trout roe, crispy fried spinach leaf, and a sliver of fried purple potato. Beautiful and delicious. Another we had was a tranche of mackerel, stuffed with foie gras and glazed with what I believe was a pan sauce bolstered with some vinegar, on top of which was balanced a long sliver of fried leek, sprinkled upon which are various salty, sweet and other flavor components - green herb powder, demerara sugar, trout roe ... you fold the sliver of leek upon itself and eat the whole thing, getting the sensations of each of the powders as you find them. All of which is to say nothing of the combination of the rich oily mackerel with the rich oily foie, a great take on a mar y montaña similar to the combination of eel and foie you see in some higher-end Japanese restaurants these days.
Bar Bergara - Bergara is a much more straight-ahead kind of style than Aloña Berri but everything we had was quite good, including a pintxo topped with juicy sweet diced tomatoes and a scatter of slivered fried onions, another with a bacalao "meatball" and a similar topping of fried onions, and one topped with salad rusa, shredded hard-boiled egg and a shrimp on top.
Casa Senra - when you see more than a half dozen different croquetas listed on the menu, including with clams and green sauce and with chipirones (baby squid), the clear message is "Get the croquetas". By an accident of translation we got the morcilla croquetas rather than the almejas I had sought, but they were still very good, scooped using an ice cream scoop, lightly crispy outside, tender and oozy inside, studded with bits of sausage. I wasn't aiming for the croquetas de morcilla because we'd also ordered the "morcillitas," a skinny home-made blood sausage that was creamy and redolent with spice, served with a green garlic olive oil emulsion and piquillo peppers. A bocata of fried eggplant, sauteed onions, bacon and cheese was also very satisfying.
More info and some pix from Aloña Berri here ->