Dk unholy or frost for pve?

Forgive my English, I'm a new player, for pve the dk is better unholy or frost? (icecrown server)

UDK is for virgins. FDK is for the chads. BDK (DPS) is for the unhinged.

I would tell you to go for unholy because many guilds don't take frost dks to raids, this is for a few reasons:

1.- Many frost players are pretty bad
2.- Frost does not offer any important buffs outside of the meele haste, and dk tank already provides the same buff.
3.- Unholy does provide an important debuff for the enemies that increases the magic damage they take, and can spread it to adds.

Now in terms of damage Unholy is better for AOE while Frost deals more singletarget damage, but because of shadowmourne the difference in single target is not much, like 1k dps difference

There are pros and cons for both specs:

Frost:
- easier to play (in my opinion)
- does more damage than unholy (single target)
- many raid leaders dont like them because they don't provide buffs for the raid, given that the DK tank has the haste buff.

Unholy:
- provides important debuff for the raid
- great AOE damage
- harder to play (in my opinion), reason i say that is, pet control, garg & army snapshots (requires buff tracking), more things to track like ghoul frenzy-desolation-have to re apply both diseases manually since you dont run major disease glyph

Sidenote*
if you have tank as your secondary spec i would recommend frost, since it allow you to go DPS on bosses where the paladin can solotank, without the raid losing melee haste buff.
If you only want to DPS and then have a pvp spec as your secondary, id recommend unholy since there is a higher probability raid leaders will have you in their raids