What DPS for Frostmourne ?

I am playing on icecrown , so far for characters i got 3 healers and 1 tank ( my main) but no dps so i think i am gonna try leveling one on frostmourne . I have no idea whats good on patches other than 3.3.5 . I am going to play mainly pve and some pvp from time to time , Whats a good class to roll ? i think i am between warlock , rogue and feral but i am open to suggestion since i have no idea whats good/fun .

Go for a warlock if you are between those 3. Rdps are always needed much more than melees and also warlocks in particular are very fun and in high demand

I will say go for demo Warlock, Its really fun spec to play and they are always in demand.