Which talents do you think are especially cool, effective, or fun to give to adversaries? I'm not thinking so much from a "beat the players" mindset, as from a "create fun combat encounters" mindset.
Some talents that I've found especially fun:
--Coordination Dodge (Performer tree): This is great for when a PC scores a lucky hit that would ruin the drama by killing a major boss in the first round. Of course you should only give it to characters who would plausibly have ranks in Coordination.
--The Force is My Ally (Sage/Seer trees): Pulling out a surprise Force power action is a great way to heighten the tension in a fight.
--Resist Disarm: Disarming can be much too easy in this system. If your players over-use the mechanic, this talent is a must.