Having lived inside the Manchester boundry for the majority of my life, Didsbury and West Didsbury are the nicest parts of Manchester to live. Unfortunately, you need a serious amount of cash to buy a house around there, so most realistic people move out to Greater Manchester or Stockport.
Nicest places to live in these areas are Sale, Altrincham, Hale, Lymm, Wilmslow, Alderley Edge, Marple, Glossop, Whaley Bridge, Macclesfield. Alot of people on here live in Cheadle and Cheadle Hulme, but don't bother moving there because the planes landing at the airport fly so low over your house the pilot can change the channel on your TV.