I visit Manchester regularly due to my kids living there (well Salford) and I've got to say I love the place.
Friendly Northern type people and always seems to be bouncing
York is by far my favourite city. The history of it is brilliant, it has everything for a history geek like me in pretty much all the periods of history I am most interested in. The other city is Lincoln but mainly the old part of the city with the castle and cathedral, again because of the history of it.