In an attempt to avoid the standard "it depends", I would say that if I raise in EP/MP and there are 3 or more players who stay in, I usually won't C-bet, unless I hit or get a juicy draw. If there are 2 players, with 1 or more tighties, I will usually bet pot to get a better read.

If I'm in LP, I think I c-bet more often, and quite often I will raise a bet in front of me if I hit top pair or pick up a draw.

C-bets should be about both reads and value, but more of one or the other depending on the situation.