I agree with Flexor. I want death to be ever present. If you blow it, it will cost you. Nonetheless, I do go out of my way to give the players a chance.
We use a house rule called the cool roll, don't ask, were everyone rolls a d12, don't ask, and the highest roll wins a karma point. The karma point allows a reroll of any roll, DM or player, and the roll is adjusted by a Karma die, 1d4, 1d6, or 1d8. This house rule has saved the day on more than one occasion. I was surprised at how close this is to the action point in d20 Modern. We thought of it first, so
I do make all vital rolls out in the open, or try to, most rolls I do behind my screen, however.
I have had players dying, -1 to -9, but the party makes it a point to stabilize downed characters. This happens quite a bit but rarely on a party level. I do hold to the -10 is dead rule.
All my players, with the exception of one, have been playing since the 1st edition days. Some of the characters they currently play were ported over.
I do not do catastrophic damage or the two 20s and die rule.
My players are very experienced and use sound strategy, maybe that is the answer to my question.
We rotate DMs as well and come to think of it, I have lost only one of my own characters, an Unearthed Arcana Paladin, the cavalier type, he charged a superior opponent that he shouldn't have.
Its nice to see that there are some DMs who share my mellowed lust for blood. I do agree that it is all about having fun and I believe that all the DMs that have answered my question are doing just that, providing fun. I know my players do. They would tell me otherwise.