I'm a first-time Death Knight and want to start playing with an Unholy spec, but I don't know what type of weapon I should use. Should I dual-wield two weapons, or use a single two-handed weapon for optimal DPS in PvP?
In my opinion, two-handed works best in pvp. Make sure you use the right glyphs, for example 'Anti-Magic Shell' and useful talents include 'On A Pale Horse' and 'Improved Unholy Presence'.
Personally, I've done better with a Frost spec in PvP but provided you use the right spell rotation, you should do fine with Unholy.
Hope that helps.
you will want to use a 2hander as unholy and 2h or dual wield as frost !
depending on the talent you pick in the frost tree and/or your hit rating
also u will want to use the rune of the fallen crusader on your 2h weapon
*btw unholy got badly nerfed in the last 2 patch so i would recoment going frost spec for dps even tho unholy is still viable frost should output more damage