Which part of aircraft is contributing the most weight of airplane?
Aerospace Engineering e-Mega Reference shows the following table for two aircraft (the large commercial jet, the B747-100, and the military jet, the C-5A). You can see that it differs quite a lot between the B747 and the C-5 already, so it's hard to give a definitive answer for all aircraft in general.

Also, it depends a lot on how you break down the components, for example, here the Nacelle and Propulsion system are shown separately, but if you combine the two (and some others as is done in the dry engine weight, I think) things could change. 
The Aerospace Engineering e-Mega Reference points to Beltramo as the source for the numbers. Perhaps you could find some information there about what belongs to which group.

However for both aircraft, it can be seen that the Wing and the Airframe are significant contributors (and for the B747 furnishing is also a large part of the weight)

I think they included all the wiring in the Avionics part (that would make sense to me), but still it is a relatively small part of the total weight.