The Old Republic

[Lissa]

P.S. Crusader, forgot to mention, there's no 'pure' classes in regards to the trees. Any AC that is a Tank or Healer also has a DPS tree and a half.

Sorta true, it's actually two trees are assigned to DPS and one is assigned to Tank or Heal. For instance, looking at the Sorcerer:

Corruption is all about healing
Lightning is all about DPS
Madness is all about DPS (but the tree is shared with Assassins which changes a couple talents to be specific to the Advanced Class)

Now, there are some talents in the first two tiers of other trees that you should grab if you do follow a Tank or Healing role.

For instance, again using the Sorcerer;
In Lightning, you'll want to take 5 talents in Tier 1 (Electric Induction - 9% reduction in force costs and Reserves - 100 more Force are pretty much must haves) and Subversion will help with your force regeneration (Lightning Strike puts a buff on you that lasts for 10s that increases Force regeneration by up to 30% - normal force regen is 8 per second). Then you'd probably grab Will of the Sith from Madness for the 6% more Willpower.

Pretty much, once you look at the trees it becomes pretty intuitive which talents will help best under what role of healing vs. DPS and PvE vs. PvP.