Back in 2e or 3e, if someone lost a character, they'd sit at the periphery of the game and work on making a new character. If they could get it done before the game was over they could join back in with their new character.
This rarely happened (usually they couldn't get one done in time) with the exception of the guy who always played wizards in 2e. His wizards died somewhere around 13 times in the course of 1 campaign (5 of those deaths in one session!) He got to the point where he could make a new wizard in about 5 minutes and be back in the game.
In my 4e game I've had ~7 character deaths through the course of Heroic Tier (including 4 in a near-TPK). In all cases except the ~TPK, the session went on and the other person whipped up a new 4e character on the Character Builder, back in 10-15 minutes(faster if they already had another level-appropriate character built on their laptop). I'd always let them fully-redesign their character after the session since they were building them so quickly.
The worst death ever was in a short-lived Alternity game I ran back in High School where the PCs were angels sent from heaven to battle demons. One of the PCs angels was killed in the first gunfight with the police (long story). In order to get him resurrected, they needed to get him to the East Coast (they were on the West Coast).
They were left $5,000 by the contact they were supposed to meet on the East Coast. The money was supposed to be for airline tickets, but the PCs said "hey, if we steal some cars, we can just drive to New York and then we'll have 5 grand!"
It took 5 hours in RL(4 days in game) of the dead player sitting there bored out of his mind as the players took out dozens of cops, stole half-a-dozen cars(the dead body transferred from trunk-to-trunk as cars were ditched/destroyed), and left a trail of destruction across the country.
When they finally got there and got him resurrected, it was late and the game ended. The campaign never had a second session (since I was looking for Blade meets the Matrix versus demons and I got Grand Theft Auto meets Fast and the Furious versus cops).