Constructive, yet Positive Feedback
I have expereinced that with each person I give feedback, it is always different. It's important to take each individuals personality, ambition, and motivation into account.
I always try to start the conversation on a positive note, even if the other knows this is a meeting of constructive criticism or for behavioral issues. I have have learned when getting to the meat of the feedback, to be direct and stick to the facts. Don't let opinion or assumptions play a part.
Then, always end with something positive the other has done or achieved.
I agree, that feedback can be different bases upon who you are talking to. Some people can take feedback better than others. I do believe however that it is all in your approach.