I make it very clear that I reward backstory. If your cleric was the high priest of a temple of Obad-Hai, people respect you, and provisions shouldn't be a problem for you in encounters with anyone halfway respectful of religion.
I find that when I include characters that are only off-handedly mentioned in the PC's backstory, the player feels special, like he is contributing to the plot, and he is interested in seeing what I interpret the character to be like.
In aswer to the OP, I prefer something along the middle. That is only in regards to experiences, though! I love detailed backstories, even if the character lived an uneventful life. Name-drops are my one true love.
I've had PCs I DMed have absolutely tortured backstories, and sometimes is stretches things a little; like, "How have you not flipped out and murdered everyone if your father lit your bed on fire if you fell asleep to keep you vigilant?"
Of course, that character did have an extremely short fuse, and his resulting brashness made for a lot of fun.
I do not dislike relatively tame characters, either, but a mix of the two is ideal. Either way, I want my players to provide oodles of details about their past!