Cornwall!
Or if you want a city, Cardiff. I was at uni there and for someone who's not a city fan I have to say I really enjoyed it there. It's a lovely city with lots of parks/green space (I belive it's more per capita than any other UK city) plus good shopping, a bit of history (Cardiff Castle etc), and the Cardiff Bay development and Marina. It's also a good base for some countryside walks, close to Caerphilly and the hills.