Depends how good u r with each character..
Without infinity, Hammerdin hands down
Hammerdin has better survivability and great damage, takes mainly just +skill items and a descent merc for hell wave 2 throne..
Light sorc has low survivability and high damage output but alot of immunes to get around.
Trap assassin has average survivability and average damage with immunes to get around also. (Death sentry helps)
Soloing with each char, I would choose Hammerdin.
Running with a group of people, I would choose trap assassin. Running with a full game of killers, I would choose light sorc
Fully geared would be a different argument.....