As you know that Wrath of the Lich King makes Warrior abilities effective, one of the most affect is Rend, which is important for wow power leveling and wow gold farming as the reliable and rage efficient attack. It has gone from a good starter in an attack to a devastating creature killer. Rend does enough damage now that it is usable and a deadly PvP weapon.
   For a Warrior, Rend is an exceptionally rage efficient ability. The Warrior inflicts base damage plus a variable on the base of weapon damage and attack power with only 10 Rage, which delivered as a Bleed effect over 15 seconds.
   On the base of weapon damage not DPS, the variable is more important to carry a two handed weapon to maximize Rend, similar in strategy to Mortal Strike, Bladestorm and Slam.
Although Rend is already Rage-efficient, the new Talents installed in Wrath of the Lich King make it devastating:
At Ranks 9 and 10, Rend will do 35% more damage to an opponent with 75% or more health.
Improved Rend will increase the damage by 20%.
Trauma increases the damage from Bleed effects by 30% after delivering a critical strike.
Taste for Blood is the key to Rend and the Arms Tree. What Taste for Blood does is that Rend delivers damage there is a 30% chance that it will allow the Warrior to use its Overpower ability.
This is pure synergy. Rend triggers Overpower, which almost always is a critical strike. This increases the Bleeding from Rend by 30%. Additionally critical strikes will occasionally trigger Sudden Death, allowing you to use Execute regardless of the opponent's health.
As you can see, Rend can do a lot of damage for very little Rage. This is very important at the early levels, where Rage and Damage can be scarce. The Warrior will be reliant on Rend, as it will be his best ability until earning Slam and Mortal Strike.
The Warrior can use the Slam rotation to level for maximum efficiency once it has learned Slam. At the beginning of Slam rotation to maximum damage and the chance for Overpower to become available, Rend should be used. When the Overpower light goes on, continue to use the Slam rotation right way.
After the Warrior gains Mortal Strike, he will continue in the fashion above, using Overpowers when available between Slams and Mortal Strikes.
Rend is very useful as well as farming. Since a well timed Rend will prevent enemies from escaping. The Warrior can use Rend and a finisher, and then quickly move on to the next victim before the first one is completely dead.
To take away a Rogue's Stealth ability is the one or the only one Rend do. A Rogue can not disappear while bleeding, so this would take away their advantage. With the new changes from Wrath of the Lich King, Rend becomes more viable.
Use Rend on as many opponents as possible in order to trigger Overpower. Overpower is one of the best abilities for PvP because of its potential to critical hit.

Rend is one of the best abilities for the Warrior whether wow power leveling, farming for world of warcraft gold or fighting in Player vs. Player. Wrath has made it even more powerful. Using Rend well means that faster leveling, quicker gold farming and absolute domination in Player vs. Player combat.