Hi, Jane,
The paradores web site has a great clickable map,
http://www.parador.es/es/portal.do and I can give opinions on some of the ones in the vicinity of Santiago. I've stayed in a fair number over the years, but usually on some ridiculous promotion that puts the price down in the $100 range (before the dollar collapse against the euro, of course).
I haven't stayed in the Baiona parador, but have been inside, walked around it, had a drink there. It's an incredible place, in a very privileged position. The fort's walls ring it, and there is water in every direction. The town of Baiona is touristy, cute, and has tons of good seafood.
Looking at the map, I came up with a couple of other possibilities, too, all relatively close. My hands down favorite is Santo Estevo, in a very remote place a short drive from the city of Ourense. It is along the Sil River Canyon, an old monastery with three or four cloisters, one of them Romanesque. Rooms are done in a modern style, very comfortable but nothing wow-producing. It's the public spaces, the cloisters, and the environment, with lots of walking trails in all directions, that is just spectacular. But the area has lots of little towns and lots of falling down ancient churches in spectacular sites. We spent two nights there last year and spent one day along the Sil River and the other along the Minho. It was great.
Other possibilities -- Ribadeo -- very pretty town on the Ribadeo estuary near the ocean. It's the place where the Camino del Norte turns south towards Santiago, right over the Asturias border, first town in Galicia. I walked the norte last summer and we stayed there one night. All rooms have a balcony that looks out over the river, and it's a very nice town. Lots of beautiful coast within short driving (or walking if you're still inclined) distance, the 8 or 10 km walk from Tapia to Ribadeo was one of the prettiest on the Norte.
Pontevedra -- another really pretty town, probably more medieval architecture than Ribadeo. I haven't stayed in the parador but have walked by it on the Camino Portugues. It's in one of these medieval manor houses and is right in the middle of the pedestrian historic distric.
Going a little further south, the paradores in Verin and Tui are both in historic buildings -- the one in Verin (on a variant of the Via de la Plata) is out of town on a hill near the castle. Nothing spectacular but in a good location for touring southern Galicia. Tui is right on the Portuguese border across the river. I was walking the camino portugues and stayed in the albergue, but we visited the parador and it's very nice, recently remodeled I think.
Of the other paradores in the area, I would not recommend Vilalba (a town on the Norte, but it's really an uninspiring place, thought he parador is in a castle tower) and Ferrol, which is not one of my favorite Spanish cities either.
So, this is probably way more information than you wanted, but I figured that it might help others with the same question.
Laurie