The Parador in Leon is fabulous, but it does have the disadvantage of being quite a way from the Cathedral, the Basilica de San Isidoro, and the old city. There are numerous albergues and cheaper options in Leon, but for those who want something more I've also enjoyed the Hostal Albany a few times, and the Hotel Paris. Both are in much better locations than the Parador. Plenty of delicious pastries in the bakery/cafes nearby!
And do take the time to visit not only the Cathedral (best stain glass windows in the world imo - pick a time when the sun pours in) but also the Basilica de San Isidoro with the pantheon of the kings of Leon, containing some wonderfully preserved 12th century murals. Give it enough time - entry numbers are restricted and through an air lock and sometimes you have to wait a few minutes.