VIT is your bread and butter stat. You want to have that as high as possible. It will typically be at cap for most of your gear anyway, but whenever you can get more, like with bonus attributes or materia melding on some gear, it's the first thing to go for as far as armor stats.

Weapon Damage is by far the biggest contributor to your damage output, and in turn has a profound effect on your enmity generation. Upgrade your weapon every chance you get if you want to keep hate readily.

STR is the next stat on the list. After Weapon Damage, it is the largest contributor to DPS.

Then you wanna go for extra Parry on PLD.

All of this, after VIT, assumes you're not missing targets. Typically as you level up this shouldn't be an issue when fighting level appropriate targets. At endgame though, you will need to reach certain Accuracy levels based on content (namely in Coil). At that point, getting Accuracy to said thresholds becomes a priority.


Also, here's a very nice source of testing data: http://valk.dancing-mad.com/