I'm looking for a place in the UK to go on holiday this year. It needs to be somewhere where there are sufficient things to do for a week. Also, I won't have my car, so everything needs to be within reasonable walking distance.
I went to York last year, which covered the above. Plenty to do and all fairly centralised. I'm now looking for somewhere else.
Then definitely try Bath, Norwich, Canterbury, Durham, Edinburgh or London (but not during Olympics). Along with others they are all beautiful and interesting and have good transport links.
I always find the train services better in the north of the country and would even suggest somewhere like Skipton for visiting Carlisle, Leeds, Howath and the local countryside.