Went for a walk in Santiago old town the other day. It is really a great time to be in town, the number of tourists are not that many so you feel like you can have the town to yourself. Not so in July :-)
A few days ago I walked throguht old town at night. The best time to experience Santiago de Compostela is at night in winter. You can walk almost alone, and feel like you are having the town to yourself.