This is way to general of a discussion, it will help to identify which circumstances you are in to best determine what suits best.
That said, it is always true that high damage is never a waste. Don't get me wrong, surviving a fight is always the uttermost important part in a fight, way more than what amount damage you can do, but high survival is definitely a waste if you can manage a full health and healing on cooldown most of the time. When you are optimizing your build, and when you are thinking survival, you should never just think solely on vit/tough. You and your group's healing ability should be the defining factor of how much vit/toughness you need, and it also defines weather vitality or toughness is better for you. If the group has strong heal, you can affort to let your health fluctuate and that benifits from a larger health pool. If that's not the case, if in a fight you feel you cannot replenish your health fast enough, then adding vitality in this case generally won't help much, toughness could be better. At the end of the day, optimizing is all about managing your resource consumption, if you have healing on cd, if you have full health pool 100% of the time, then your resources are wasted.
I myself play a warrior and a thief, and I am a advocate of damage mitigation via toughness and skill/traits. Like CepaCepa mentioned, your vitality might need a threshold in most cases, but after that, my personal opinion is they are quite useless if not special situation calls for it, for example you are kiting mobs for whatever reason. Dogde, blind, block and condition removal (even swiftness) should always be your first resort for survivability, period.
In general, I would say the most effective way would be to build enough survival to suvive whichever situiation or playstyle you are looking at, and then strip them away to the bear minimum in favor of dps. If it just happenens you can strip away everything to a glass canon, then there you go, that's the best way to.
Lastly just to throw in my favorite quote: "A dead dps is no dps."
Edited by Cannot See Me, 08 January 2013 - 05:34 PM.