+1 for Edinburgh. The council services are appalling for residents but it's an amazing city for a tourist. Loads to see, the Castle, Royal Yacht Britannia, Museum of Scotland, the Botanics, the Forth Bridge, loads of galleries, loads of top class restaurants, loads of places to enjoy just walking about.
A couple of other Scottish options -
St Andrews is a very pleasant place to stay, very well heeled, lots of interesting places to visit in the vicinity.
Glasgow is somewhat less refined, certainly rougher around the edges (some would say more authentic) but lots to see and more than enough nice hotels and restaurants.