In Manchester you are in the middle of Joseph Holts territory. You should have a look at the brewery's website. It's the cheapest beer for miles, served in genuine pubs but it's a strong and heavily hopped, dark bitter, maybe too bitter for some. Holts own all their pubs and their city centre pubs are getting through two hogsheads a day so the beer is guaranteed fresh. When you drink it you'll realise how many stale, warm and flat pints you've been served in your life.
Here:
http://www.joseph-holt.com/
Other good local names are Phoenix from nr Rochdale, Leyden from Bury, Moorhouses from Burnley, even Thwaites from Blackburn is okay. If you had time you could travel out of town to some great pubs like the Robin Hood in Helmshore, the Porter's pubs in Rossendale or the Lord Raglan near Bury, home of Leyden Ales.