Since it has come up a few times, I thought I would review why I like death being on the table for PCs in my game. I'm not saying you can't achieve similar ends without character death, but that with character death on the table, these are the benefits I have seen

1. You can still have non-death consequences, death doesn't need to be the only consequence.
2. Since players know they can die, they only fight when they have to
3. Since they know death was at stake, when they are successful, it feels like an accomplishment

4. They feel more immersed in the game, I don't break immersion with obvious saves and favorable rulings
5. It produces consequences when you kill, that must be dealt with in game
6. It produces moments of cooperation, where the party comes together to protect vulnerable members

7. It produces interesting discussions about violence and its use
8. It leads PCs to look for the value of their opponents before killing them, as once dead they are generally gone
9. It leads the party to look at others as possible allies and thus not immediately kill them

10. It leads to a game with less frequent, but more deadly combat
11. It allows players to try out new character concepts, something they might not otherwise do
12. It builds skill as a player as they figure out how to avoid death

13. It creates excitement at the table as we know rolls could represent character death, not just a setback
14. The party is inevitably made up of NPCs, and 'secondary' PCs (in many games my players run 2 PCs), the death of a PC ups the excitement levels

15. A glorious death while saving your party (which happens a lot) is celebrated and remembered

I'm sure there are others, add one if you can think of it!