5.0 Rogue Talents
First, get to know The Three Talent Trees and each talents. It might help to use a talent calculator.
Assassination - Burst or Frontloaded Damage, Critical Hit Increases, More potent Finishing moves and Poison Improvements.
Combat - Sustained Damage and Passive Bonuses and improvements to Open Melee Fighting.
Subtlety - Stealth Improvements, Opening Move Improvements, DoTs, Energy Conservation and Cooldown Control.
Most builds try to utilize two of the three major 21pt talents: Cold Blood, Blade Flurry and Preparation. Other builds try to incorporate a 31pt Talent: Vigor, Adrenaline Rush or Premeditation. With the 31pt talent, be sure to pick up the 21pt talent in that tree as well but be forewarned that grabbing a 31pt talent will limit your flexibility and customizability of choosing your talents as they we mostly be in one talent tree. The builds below are fairly common and keep in mind there are variants for all of them and as long as you keep the key talents, are fully customizable. The talent builds are simplified to a series of numbers separated with a "/" to read as Assassination/Combat/Subtlety. (eg 21/8/22, 31/8/12)
No matter what build you use, get Improved Sinister Strike first. Let me also say that for grinding I think Remorseless Attacks 2/2 is the best talent as it gives you a 40% opportunity to Critical that next Ambush leaving your same level mob with around 60% of his health. Once fully specced with malice and Imp. Ambush that could bring its crit chance up to over 100%. Thats like a free CB for 20 sec after every kill from a green or higher mob.