I am playing an elf barbarian and planning to work towards shadowdancer ASAP. I have decided that the rage ability is best used only for minor encounters. My rational is that fights against major encounters are more likely to bring the character to unconsciousness. When not raging, this would mean a chance of instant death but also a chance of simple unconsciousness, and if the monster is otherwise occupied, the likelihood that I would survive. But if raging, while I would last a few more rounds against the monster, and even have a chance of putting it down, if I were to go unconscious, my rage would instantly end, sending my already negative hit points plummeting, and making instant death much more likely. So if I use up rage rounds only on minor encounters, I at least speed the resolution of such encounters, allowing the party to conserve their resources for the major encounter. Does this rationale make sense? Oh, available texts are the Pathfinder Core Book and the Advanced Players Guide (and the DM will have Bestiaries). I was thinking of getting the feat Raging Vitality at level 9 (my con is only 13 at level 1) and the rage powers Guarded Life and Renewed Vigor at levels 2 and 4.
