Yet another silly question time....
 

When making a banked turn - do you turn the yoke until the aircraft reaches the desired bank angle then LET IT RETURN TO NEUTRAL and the plane should remain turning in the bank? Or do you have to physically 'hold' the turn??

Depends on the aircraft. Some are more inherently stable than others.

Say, a 737?

Haven't flown a 73 but on it's bigger brother (and most non FBW a/c) you roll in, reach desired bank, then almost neutralise aileron - but not quite.