ok lets get some math in here brothers
the normal sword would deal 100 dps a second, and assuming all of these have the same hit chance, we can figure out which enchantment is the best!
Fire would deal 150 dps
Frost would deal 100 dps (and slow 50% attack and movement)
Poison would deal 100 dps
Thunder would deal 100 + .5((number of nearby enemies)50) dps
Blood would deal 100 dps and have 50 hps
Diamond would have 150 dps
Spikes would have 100 dps plus 50 dps to attacker
Haste would have 150 dps
ethereal would have 100 + ignores armor
Ghost would have 150 dps
Death would have 100 dps + 2% insta-kill chance
Demon would have 100 dps + .01(enemy health)
Drain would have 100 dps + -50 mana per second
Explosion would be 100 dps unless they die then it would be (number of nearby enemies)75 dps
Rage would have 100 dps + .01(your health)
Curse would have 100 dps + 50% armor
the best possible choice would be Demon Rage with your health at 1% and your enemies health at 100% for maximum damage