I'll try =P I'll keep it short, dont have much time.
Subtlety
Most subtlety talents increase your stealth abillity, and your ability to strike from stealth. Also some neat utility talents, like imp. sap and preperation, that come in handy in instances or PvP.
Combat
Really a damage-dealing tree, focusing on non-stealthed attacks and high sustained damage output. Many rogues go deep into the combat tree, and use a high damage/slow attack speed mace or sword to do damage with sinister strike. Newbs
Not really the best to go deep into combat if you plan on major PvP or battlegrounds action, burst damage can be hard to come by.
Assassination
Another damage-dealing tree, mainly focusing on increasing the damage done by attacks, and critical strike chances.
This is the build I used, it worked great for PvP and I was never far behind the pure combat rogues in MC once I got my Gutgore Ripper.
Subtlety Mastery
Master of Deception Rank 5
Opportunity Rank 5
Initiative Rank 5
Improved Ambush Rank 3
Improved Sap Rank 3
Preparation Rank 1
Subtlety Total: 22
Combat Mastery
Improved Gouge Rank 3
Improved Sinister Strike Rank 2
Improved Backstab Rank 3
Combat Total: 8
Assassination Mastery
Improved Eviscerate Rank 3
Malice Rank 5
Ruthlessness Rank 3
Murder Rank 2
Relentless Strikes Rank 1
Lethality Rank 5
Improved Instant Poison Rank 1
Cold Blood Rank 1
Assassination Total: 21
Total
Total Points Spent: 51
Level Required: 60
Hope this helps a little bit.