I think the best answer I can give you is... It depends.
You don't ever want to c-bet multiple players. Chances are good that the flop helped one of them. If you are in a heads up situation then you have to decide what kind of player your opponent is.
If it's someone who like to draw, will call with overs, or call down with bottom pair to the end, a c-bet would be pointless and just cost you money. Instead you need to be looking to hit your hand and then value betting these players.
If it's someone I have seen fold a lot of hands post flop, I am going to c-bet them everytime I raise preflop. The times they fold more than make up for the times they call.
Also remember too, just because they called a raise preflop doesn't mean they have a big hand or even big cards. They could have a small to medium pair or some kind of low to middle suited connectors. If you raise preflop with a pair of J's and the flop comes out A K 7, I think you have to fire a c-bet. They don't know you raised with J's and they could of called your raise with a pair of 5's. If that's the case they fold to your c-bet. If you get called you can slow down if you like or get raised you can throw them away if you want too.