James L.
Yelp
Here is my personal ranking of San Sebastian pintxos bars: Casa Urola, Sirimiri, Gandarias, San Telmos, Goiz Argi, Sport, Ganbaras, Fuego Negro. I will write the reviews here since Gandarias is open daily, pretty much at all hours. Many popular ones are close on Sundays or Mondays, and are usually only open during certain hours. This will be a good intro to the SB pintxos scene, obviously there are others like Zeruko, La Vina and Borda Berri which I didn't try and thus can't comment. Definitely get the shrimp skewers and mushroom skewers at Gandarias if you are eating at the bar. There is a sit down section as well if you want a more traditional way of eating.
Casa Urola is the best, you can order hot pintxos at the bar, which are all excellent. But I'd try to reserve a table upstairs if you can.
Sirimiri is the sister restaurant to the more popular Atari at the corner. It's much smaller, but usually not as busy. The cold pintxos are good but the hot ones are even better.
San Telmos is probably the most talked about place and everything is made to order. I am not rating it higher only because everything is rich and on the greasy side, but they are definitely good taste-wise. Show up early right when they open so you don't have to wait.
Goiz Argi has the grilled items made to order. The kidney is simply divine. Gandarias' shrimp skewers are probably better though.
Sport has a couple of unique seafood items but I don't think their items are better than others. However, their service was the best among all the places I tried. They try to actively engage you even when the place is mobbed, so I definitely appreciated that.
Fuego Negro has the fried squid ink which is a must get. The kobe burgers are okay. Skip the fried chicken, for us Americans it probably will underwelm and the large portion will preclude you from eating at other bars.