Having lived in many places, all across the UK (33), IMO it's about what's right for you at that time.
London is good for the single person but perhaps not for buying a house.
Manchester, and some other cities, is also good for the single person and as you indicate, can offer some affordable houses - to buy or rent.
But don't be fooled into thinking it's cheap up north!
http://www.manchesterlettings.org.uk