It depends.

As much as I don't mind seeing my characters die often in a dungeon crawl (what I like to call "tomb-raider parody") because the goal is to be the more genre-savvy bastard there is, I prefer the deaths of my chars, if they are permanent, to be a bit more meaningful in a story-driven campaign.

Dieing because of a fumble on a ride check (very bad DM) or because I failed a spot-check in a dark alley would have no purpose, I feel, if the campaign depends heavily on the characters. Alternatively, dieing in combat because of bad rolls/decisions/whatever is ok because it would enhance the story.

What I meant to say is: don't pull your punches but don't be an a**hole either.