Hmmm. Probably hp loss.
In my two most recent home campaigns:
Campaign 1:
Death 1: hp loss. But, when the orc archers behind cover and 120' up a hill responded to his taunts by saying "come up here and we'll show you how orcs fight," he obliged.
Death 2, 3, and 4: hp loss again. But they lost hit points because I tossed a difficult encounter at them and they proceeded to A. Roll poorly (1/2 the party failed their saves against mummy fear and though not CDGed while paralyzed, they lost enough hit points that they never recovered). B. Make poor decisions--the fighter wizard (who made his save against the fear) cast invisibility on round one and spent the next three rounds buffing himself. C. Failed more saves--the rogue/bard failed his save against a hold person. D. Make more poor decisions--the fighter/wizard decided, as the last man standing to stay "just one more round."
Death 5: Self-sacrifice. The cleric decided to hold the evil priest off while the others could escape. Then again, they only needed to escape because they'd spent hours searching behind bushes for their stuff after escaping from the prison and the evil priestess came back to collect her sacrifices.
Death 6: Gullibility. So, you've decided to go to the seedy area of town because you've heard that an old woman there might have a spellbook for sale. You ask if you can buy healing potions too and she says "sure." She then comments that the villains have a price on your head. So, you say, "can we buy the potion." She says, sure, you can buy the "healing potion." So you do. Then she brings the spellbook out and you recognize it as your own (which the bad guys captured from you two sessions ago). Then it turns out she's a hag and she tries to kill you and your friend. So your friend, who's down at negative hit points says "give me the healing potion we just bought." So you do and I say, "make a fort save" and all of a sudden your friend says, "so I guess it wasn't a healing potion...." Long and the short of it--that death goes down to con damage.
Death 7. Delayed reaction from character construction. So, the fighter/mage, who's lived longer than any 8-con character has a right to live (and is, ATM, the last surviving character from the first group of characters) tries to go toe to toe with a pair of fiendish girallons. He doesn't.
In my more recent campaign, the only PC death so far is also from hit point loss--in this case, falling damage.