In the many campaigns I have run over the years, the death rate has varied greatly. I think when you are with a group for a while, you get a feel for what they like as well as what you like when dealing with death. I've had characters from "I died once and was resurrected. If I die again, I'm staying on the other side." to "I died again. How much does it cost?". Personally, I'm good either way.
I think a lot of factors go into it. I remember switching from 2nd Edition to 3.0 when it was new. Threw a couple of Ettins and bears at the party and got a real wake up call about what Reach and Attack of Opportunity really meant. So did the party. :) That wasn't their fault.
Then there was the low level guy that charged the Hill Giants at the top of a hill. That was stupid.
Ultimately, the point of the game is to have fun. Even to know your character died once can be painful in itself. No one wants to be "that guy" that always gets creamed because of stupidity. If the party is getting slaughtered even though they are playing smart, then the encounter is too tough...and that is the fault of the DM.