i was just wondering what is the best pve race for the horde,
orc, troll, or blood elf?

I have an Orc as rogue because of the bloodfury which gives extra damage. A orc rogue looks awesome also.

troll.
haste effects are tremendous increases that scale with your gear as you get into higher and higher teirs.
bloodfury does not scale with your gear, only your level. when you first hit 70, the orc racial is better statistically, but once you have a little bit of gear, the troll racial is considerably better.
the majority of a combat rogue's damage is from white hits. any minor increase to attack speed produces a large result on the meters. 10 percent is equivalent to a 174 haste rating (with a 2.6 speed weapon at lev 70)

Troll

Berserking is significantly stronger than the Orc racial if you got decent equip and its even stronger if you're on low health (the Orc one is weaker, because of the heal debuff), which might be the moment you need it most.

Regen gives you more endurance in long fights and 5% more dmg on beasts never hurts. Same for getting a nice crit deadly throw a bit more often if the mob runs away ;o)

Undead males looks the sickest when it comes to swinging maces and hammers but daggers r gay....

ok what race is the best for rogues? Hands down undead are  the best their racials are awesome.

Will of the forsaken is awesome immune to Fear, Sleep, and Charm effects. Can also be used while already afflicted by Fear or Sleep

cannibalize, regenerate 7% of total health every 2 sec. by consuming Humanoid or Undead corpses within 5 yds

underwater breathing lasts 300% longer than normal. when you get your lp higher lvls to like 185+ you have to go underwater to pick locks and it helps that you can stay down longer than everyone else.

and +10 to shadow resistence.

Also Ud lvl alot faster....

you should have red the question...its not "what is the best race for rogues?" (which is UD, i agree) its "what is the best race for PVE?"
WOTF is great in PVP, but usually does diddly in PVE (there are some mobs that fear e.g. in dungeons, true, but the argument that your group will be whiped if you dont have WOTF by getting feared and thus aggroing additional mobs is rubbish, if that happens to a rogue you vanish and thats it. since the normal raid group is not made of UD only its much more common that happens to someone else that a rogue...i dont recall a group beeing whiped with a rogue to blame...its usually a fury warrior ;o)

UD lvl faster? how do you come to that conclusion? because you can stay longer under water? 10 shadow resistance? cannibalize?
last one saves food, great...i still bet a troll rogue grinds any group of mixed mobs faster than an UD.

So THAT'S why there are so many UD Rogues -_-

I guess Troll, and Trolls do really good as sword rogues too. I chose an Orc because i never figured out Trolls get + attack speed so yeah...
Orcs get an + damage with is good for raiding and soloing when you have no downtime other wise its not that good. Its also a fast cooldown and for combat is like the same length as blade furry.
Having a level 70 orc rogue and a level 24 Troll rogue, i like the orc better but trolls might be better and probly are then orc rogues. but orc rogues also get + 5% to stun and fear resistance that helps on pve fights with fear.

Gnome eats all!