Annihilation is a dot-spec, carnage is burst and rage is aoe-smash-thingy(I think). Annihilation and carnage are the PvE trees, but should both work in PvP as well. Rage is PvP only. Since I dont do PvP I cant really say much about that, but for PvE I use carnage myself. I've never actually tried annihilation, but apparently its the about the same damage as carnage over a long period of time. However, a lot of raid bosses require burst damage, so I stick to my carnage.
Str is obviously mainstat. Endurance you dont need to think about. Crit rating should be at ~25% unbuffed (~30% buffed) and surge at ~75%. The closer accuracy is to 110%, the better(apparently). But you shouldn't overthink such stats too much. Just go for the weaponmaster set and you'll end up at okay-ish stats. Different stats goes up and down depending on which item you switch out when going to the higher tier. Obviously get everything augmented with might augments.
My stats unbuffed:
Str: 1925
Endu: 1722 (~19.9k hp)
Power: 601
Accu: 105.17% (258 accu rating)
Crit: 24.73% (163 crit ragin)
Surge: 75.21% (267 surge rating)
Buffed with stim I'll end up at ~2150 str, 20.7k hp, 29.73% crit and some extra power. I stacked a lot of power by doing custom belt/bracers with the str/endu/power augments from black hole boots/legs. With good might armoring it's better than the campaign ones.
http://swtorhumanrelations.com/2012/01/18/sith-marauder-guide/
I used this once (atleast for items), but it's getting more and more outdated, especially when it comes to skilltrees. Also I never cared much about the accuracy, just don't rip out all of it.