Stormborn
Explorer
Dwarves would be my first choice for most settings, making humans the magical race and dwarves the technological one.
However, I voted Other just to be different: Warforged. OK, I know they may not fit the catagory requirments (demi-human is an artifact term from older editions and basically means "humanoid", right?) but I think could provide the most interesting setting. You could run it any number of ways. Go BSG and have the warforged be antagonistic creations that have rebelled against their makers. Play them as a race of constructs who have no knowledge of who made them, but have creation forges that make a certain number every year, or magical only when one "dies", that live in their own cities. Make them a new race created by a powerful and secretive band of wizards. Change the flavor and make them more clockwork. Let them be the creation of a race of dwarves that is long since dead. Could be intersting.
However, I voted Other just to be different: Warforged. OK, I know they may not fit the catagory requirments (demi-human is an artifact term from older editions and basically means "humanoid", right?) but I think could provide the most interesting setting. You could run it any number of ways. Go BSG and have the warforged be antagonistic creations that have rebelled against their makers. Play them as a race of constructs who have no knowledge of who made them, but have creation forges that make a certain number every year, or magical only when one "dies", that live in their own cities. Make them a new race created by a powerful and secretive band of wizards. Change the flavor and make them more clockwork. Let them be the creation of a race of dwarves that is long since dead. Could be intersting.