Mine is "torta del casar" (from Extremadura), very soft but strong taste and smell, delicious, to be eaten only with bread and red wine.
I love also Arzúa-Ulloa (Galicia), very soft and fresh, excellent to be eaten with honey as a dessert.
I like very much the Mahon cheese (Menorca Island), specially when it is very mature (something betwen cheedar and parmesano). I make sandwichs with olive oil an fresh tomato, red wine to drink with it, of course.
Afuegalpitu is also delicious, hot and tasty.

http://www.cheese.com/countrystep2.asp?Country=Spain

Oooh! Ooh! Me too! I LOVVVVVE "torta de casar". AS you say, it's quite "bitey". Mmmm... So good and creamy, spread on warm toast. Mmmm...


I've also always liked the soft Galician cheese, "Tetilla".

Now here's a subject I can get into, CHEESE! I love cheese and was about to list cabrales as one of my favorites until I read about it on the link above. I'm going to trust the mercados don't carry that extreme version! yikes!
Back to favorites...i know it's typical but I have to say, there's nothing like it when you've got a good manchego curado in your possession.
I like san simon as well, from Galicia. I'll eat smoked anything!
Cuajada and Burgos are good too. Oh, man, just list them all!!!

Great topic starter, Valenciano_en_Madrid! I will agree with you that Mahon is one of my favorites and also with nevado that you can't go wrong with a nice queso Manchego. A few others that are a bit stronger that I like are Ibores (from Extremadura) and Ronda. I recently tried Garrotxa and thought that was tasty, too. I'm going to look for that torta del casar that you and MadridMan recommended so highly!

OTORKI from the basque region of Spain. and of course Manchego .

I forgot the "quesuco de Liébana" from Cantabría. Specialy the smoked one. Wow! Incredible taste, very good with natural spanish cider. MMMMM!!!

http://www.quesos.com/enciclopedia.asp?P=Region
http://www.guiamiguelin.com/quesos/do.html

http://www.sidra.com/
http://www.sidradeasturias.es/res1024/en/actualidad.php