Have you tried the 'Harper Hall' trilogy? (Dragonsong, Dragon Singer and Dragon Drums) (which if you like them could lead to 'Dragonriders') - also there was a 5 or six book series...oops - I just checked here it is a seven book series - called 'Starbridge' -won a bunch of awards - has a lot of thought provoking stuff without sacrificing a 'good read'

The 'Starbridge' series was what got my niece reading for pleasure when the first book came out.