Titan's Grip is a powerful ability that allows the Warrior to dual wield two-handed weapons, at the cost of a 10% damage reduction. Fury is the de facto "dps" spec for PvE, but miles worse in PvP.Armor Penetration and Strength are tied as the most important stats for this spec, with haste not being quite as important. That, coupled with the Rend talent in arms, will ensure that Overpower is up nearly 100% of the time - other talents will ensure it has a 50% crit chance. At 15, characters should immediately pick up the "Overpower" glyph that allows the use of Overpower if an attack is parried.
At the lower levels, characters with heirloom items (BOAs), especially the two-handed weapons, may wish to spec into Arms because of the large number of instant attacks based on weapon damage - Overpower and Rend being your two staple moves. Arms is generally for PvP, but can also be used for PvE very effectively with the right talent choices and a coupling with fury.Cannibalize is pretty useful when questing, because you don't need to bring as much food to recover lost health(though funny when used on other players!), and underwater breathing can be useful on particular quests - where you need to kill mobs underwater - and the +200% time to breathe under water will save you rest time. Will of the Forsaken has certain advantages, but largely is case-by-case for an Undead Warrior. Warriors innately get Death Wish, however, which can be used in any stance. Undead characters start with Will of the Forsaken ability, which is handy in many later boss encounters.However, Trolls also receive an attack speed increase which is very useful. Trolls receive a health regeneration bonus - at higher levels this regeneration becomes marginal. Trolls are good if you want to be a fury warrior.Tauren are probably your second best choice, the 5% addition to base health is very useful, and their Warstomp ability (stun targets in an area) can get you out of some sticky situations, a much overlooked ability is the 8 yard (7.3 m) melee range, this can be CLUTCH in PvP.At higher levels, the healing becomes marginal, but when combined with the heal granted by high-level Herbalism, it can suffice in a pinch or aid with rapid pulls while soloing as a non-healing class, if you haven't specced into Bloodthirst. This HoT is pretty nice at low levels for soloing. The other main racial they have is a heal over time(HoT). Also, 1% hit rating is important for a warrior, as it opens up other gem / enchant choices such as stamina or strength. This 1% becomes essential in high-end raiding, as most casters factor this hit rating into their gear choices. Draenei have a very strong raiding racial - a passive aura that increases other party members chance to hit by 1%.It gives a 10 to frost resistance, (kind of negligible).