The Fall was the best band to ever come from Manchester. There are hundreds of releases from Mark E. and company (you could say he's the British Pollard, except that the Fall are still making good music). If you could only buy three releases by the Fall, I would start with:

This Nation's Saving Grace (1985)
Hex Enduction Hour (1980)
Totally Wired: The Rough Trade Anthology (2002)

That's a good start on some absolutely essential listening...

As for the bands in 24 Hour Party People, I would start with:

Joy Division's Unknown Pleasures and Closer albums, New Order's Power, Corruption and Lies and a recently released compilation of A Certain Ratio tracks, Early.

The Happy Mondays stuff is crap, but their part in the movie was hilarious.

OH.......I completely forgot about the Smiths....that's a whole different subject....in my book they still come third after the Fall and Joy Division.
I know i'll get shit for that.

The Stone Roses, either their first eponymous album or the greatest hits.

The Charlatans U.K.'s best album is probably their first, Some Friendly.

The "Madchester" page at Allmusic.com is a decent place to start your search.:

http://www.allmusic.com/cg/amg.dll?p=am ... &sql=C4391

I had a huge Madchester phase a few years ago-- seeing 24 Hr party People sort of broguth it all back. Was never too much into Joy Division, though. Never was that depressed, I guess.

English people are .