Ranger: which self buffs are worthwhile?

[port9001]

As a Ranger I have quite a few buffs I could keep up on myself, but it's not overly clear which ones are worth the effort.

I pretty much take it as a given that my AC+DS buff and Skin buffs are worth it for the extra AC, with the light DS or HP being a nice side benefit. It helps that these are long lasting anyway. But maybe this is a poor assumption. How much AC actually matters?

SoW obviously.

Now for the shorter lasting buffs that are somewhat more annoying to keep up at all times:

Firefist- this gives +12 ATK. Is this worth it? I tried some parsing today and over the course of a few hour solo session it parsed out to be 5% more DPS but the sample size feels too low to say anything definitive. Is it possible for 12 ATK to give that much DPS? Doesn't seem right.

What about strength? This should affect ATK as well as max hit right?

Call of Sky feels worth it, at least to me as a 40's Ranger. I can expect it to fire off enough times to be a pretty efficient nuke.