[Gimli]

Still your pure casters are going to have pretty poor hit points even with a high Vit. And there are spells/tactics that I would prefer using to avoid being damaged over raising Vit. Things such as stone skin, guardian angel, party formation changes, etc. Like if someone goes insane and no one can cure it with a spell, walk every combat round so that no one will have enough movement left in the round to attack. Better yet take out casters before they get the chance to make you insane.

I usually go with str/dex first for fighter types and int/dex first with mage types. But pretty much anything will win so there's no best way.