In reply to pasbury:
Winter Hill: a city on one side, a moor on another and a country park on another side. Great views across most of the North from the Lakes to Snowdon and the North sea. Riddled with mines, some of which periodically collapse allowing exploration before they are quickly filled. Suspect I have walked, run, biked and skied up it over 200 times.
Auchineden Hill: one of the best views in the UK with the bonus of some climbing in the Whangie. Nearby Finnich Glen is also a treat.
Pendle Hill: not the most amazing view or inspiring walking but more an eerie place. The M65 corridor always feels like the 'wild west-frontier' of the UK (to me) and the history of Quakers, witch burning and the like cover the hill in mystery. A pint in the Swan With Two Necks and lunch at Northcote quickly restore order.
Harborough: climbing aside, there are stunning views north and south, and much fun to be had in the old mine workings. Cycle along the High Peak trail or walk from anywhere other than the cement factory.
Castle Hill, Cambridge: barely a hill but every time I went up there I felt I had escaped from the city. Sunrises were particularly good.