(A new version of this post has been created for the changes made in Game Update 2.0. We'll keep this post around for posterity. -Teo) It seems every time I look for one of these online I end up with a dead link or a random reference that doesn’t help. So here they are. Note that they use the same general name for both PvE and PvP gear; for instance, the Vindicator gear name is used for Sith Warriors and Jedi Knights for both PvP and for PvE sets. But the sets do not mix and match; 3 pieces of PvE Vindicator and 1 of PvP Vindicator will not give the 4-piece bonus from either set. The name (example: Vindicator) will appear in the name of every item of the set. This includes items (like belts) which don’t count towards the set bonus; they share the name because they generally are itemized for the same use. Only head, chest, leg, feet, and hand pieces will count towards 2- and 4-piece bonuses. The 2-piece and 4-piece information below is from information found in-game, and is copyright BioWare.

Sith Warrior (Marauder and Juggernaut) and Jedi Knight (Sentinel and Guardian)

Vindicator	PvE	2-piece	Lowers the cooldown of Enrage or Combat Focus by 5 seconds
		4-piece	Reduces the minimum range of Saber Throw by 10 meters
	PvP	2-piece	Intercede or Guardian Leap heals you for 8% of your total health
		4-piece	Increases all damage dealt by 10% for 5 seconds after using Force charge or Force Leap
War Leader	PvE	2-piece	Increases the duration of Blade Turning by 1 second, and the duration of Invincible or Warding Call by 2 seconds
		4-piece	Increases the amount of damage absorbed by Sonic Barrier or Blade Barrier by 20%
	PvP	2-piece	Increases the duration of Force Choke or Force Stasis by 1 second
		4-piece	Increases your damage dealt to players by 5% while you Guard another player
Weaponmaster	PvE	2-piece	Reduces the rage cost of Vicious Throw or Dipatch by 1
		4-piece	Reduces the cooldown of Frenzy or Valorous Call by 15 seconds
	PvP	2-piece	Reduces the cooldown of Undying Rage or Guarded by the Force by 15 seconds
		4-piece	Increases the range of Vicious Throw or Dispatch by 5 meters

Sith Inquisitor (Assassin and Sorcerer) and Jedi Consular (Shadow and Sage)

Force-Master	PvE	2-piece	Reduces cost of Lightning Strike and Force Lightning or Disturbance and Telekinetic Throw by 2
		4-piece	Affliction or Weaken Mind damage has a 10% chance to increase alacrity by 5% for 15 seconds.  Cannot occur more than once every 20 seconds
	PvP	2-piece	Reduces cooldown of Crushing Darkness or Mind Crush by 1.5 seconds.  Crushing Darkness or Mind Crush damage heal you for 0.5% of max health
		4-piece	Increases range of Shock and Jolt or Project and Mind Snap by 5 meters
Force-Mystic	PvE	2-piece	Reduces cooldown of Innervate or Healing Trance by 1.5 seconds
		4-piece	Increases total Force by 50
	PvP	2-piece	Reduces the lockout debuff duration of Static Barrier or Force Armor by 3 seconds
		4-piece	Consumption or Noble Sacrifice restore 3% of max health over 6 seconds
Stalker	PvE	2-piece	Saber Strike hits restore 1 Force
		4-piece	Increases the critical chance of Thrash and Voltaic Slash or Double Strike and Clairvoyant Strike by 15%
	PvP	2-piece	Increases range of Force Slow and Jolt or Mind Snap by 5 meters
		4-piece	Increases Recklessness or Force Potency charges by 1 and reduces its cooldown by 15 seconds
Survivor	PvE	2-piece	Increases shield chance by an additional 5% during Dark Ward or Kinetic Ward
		4-piece	Increases Elemental, Internal Kinetic and Energy damage reduction by 2%
	PvP	2-piece	Reduces cooldown of Spike or Spinning Kick by 10 seconds
		4-piece	Increases your damage dealt to players by 5% while you Guard another player

Bounty Hunter (Mercenary and Powertech) and Trooper (Commando and Vanguard)

Combat Medic	PvE	2-piece	Increases the duration of Supercharged Gas and Supercharge Cells by 3 seconds
		4-piece	Reduces the cooldown of Healing Scan or Advanced Medical Probe by 1.5 seconds and the cooldown of Emergency Scan or Bacta Infusion by 3 seconds
	PvP	2-piece	Increases the duration of Energy Shield or Reactive Shield by 3 seconds
		4-piece	Reduces the cooldown of Healing Scan or Advanced Medical Probe by 1.5 seconds and the cooldown of Emergency Scan or Bacta Infusion by 3 seconds
Combat Tech	PvE	2-piece	Reduces the cooldown of Explosive Fuel or Battle Focus by 15 seconds
		4-piece	Increases the damage of Rail Shot and High Impact Bolt by 8%
	PvP	2-piece	Increases the duration of Carbonize or Neural Surge by 0.5 seconds, and reduces the cooldown of Determination or Tenacity by 15 seconds
		4-piece	Increases the critical chance of Rocket Punch or Stockstrike by 15%
Eliminator	PvE	2-piece	Increases the critical chance of Power Shot and Tracer Missile or Charged Bolts and Grav Round by 15%
		4-piece	Reduces the cost of Rail Shot by 8 or the cost of High Impact Bolt by 1
	PvP	2-piece	Reduces the cooldown of Jet Boost or Concussion Charge by 5 seconds
		4-piece	Increases the critical chance of Rail Shot or High Impact Bolt by 15%
Supercommando	PvE	2-piece	Increases the duration of Oil Slick or Smoke Grenade by 2 seconds and the duration of Energy Shield or Reactive Shield by 3 seconds
		4-piece	Increases Melee, Range, Tech and Force defense by 2%
	PvP	2-piece	Reduces the cooldown of Heat Blast and Jet Charge or Energy Blast and Storm by 1.5 seconds
		4-piece	Increases your damage dealt to players by 5% while you Guard another player

Imperial Agent (Operative and Sniper) and Smuggler (Scoundrel and Gunslinger)

Enforcer	PvE	2-piece	Increases the critical chance of Backstab or Backblast by 15%
		4-piece	Increases maximum energy by 5
	PvP	2-piece	Increases the duration of Infiltrate or Smuggle by 5 seconds and Evasion or Dodge by 1 second
		4-piece	Increases max energy by 5
Field Medic	PvE	2-piece	Reduces the energy cost of Recuperative Nanotech and Kolto Cloud by 4
		4-piece	Increases the critical chance of Kolto Infusion and Kolto Pack by 15%
	PvP	2-piece	Increases healing done by Recuperative Nanotech or Kolto Cloud by 15%
		4-piece	Increases max energy by 5
Field Tech	PvE	2-piece	Activating Target Acquired or Illegal Mods restores 10 energy
		4-piece	Reduces the energy cost of Takedown and Quickdraw by 7
	PvP	2-piece	Increases the duration of Orbital Srike or XS Freighter Flyby by 3 seconds
		4-piece	Increases the range of Distraction and Takedown or Quickdraw by 5 meters