I'd go for something like a good solo class and use the dirge to make them an even better all rounder. That means you're looking at summoner, druid, brawler or crusader. Personally I'd lean towards the necro or the sk as you're doing the same damage type, you're debuffing the same same damage type. At that point I'd go for fingerwaggler/fighter whatever you prefer.
My son, who is only 5, and I have duoed a Fury / Dirge combination to 60 thus far. (he is 62 with the dirge and the Fury is 59.9 ) We also have a Pally / Warden combo as well in their 40s and a bruiser / templar in the 20s. While all are fun, the fury dirge combo is amazing, I can't think of anything better. (except maybe my Monk [main] and a Fury) With the dirge songs my fury NEVER runs out of mana. At 62 and 59 we are taking 4 to 5 64^ at a time in Sky. My Fury is Stormcaller speced and the Dirge is a minstral INT (don't see people promoting that but she was out damaging a level 69 AGI specced in PoA the other day so go figure...). The fury can port them around and the dirge, with regen healing can tank just fine. We usually do half the armor melodic and half normal for the extra STA. I would definitely consider a Fury to play with the Dirge, both can also solo VERY well and together they just rock. We also have made a lot of plat with them because of their ability to pharm areas w/o a group. (SH, Varsoons, RE etc...) Marb
I used to duo with a Warden... of course that warden was Daarkstar so Me(Lourdes) and him, we were pretty unstoppable even against full groups... we took out Brokensword and Kaily a few times LOLOLOL... and if any of you know Brokensword and Kaily, you know they are a very strong duo... but I can pretty much one shot kaily so lololol again lol.
Me and my wife have 2 dirge duo's, the first is her troub and my dirge, we have made it into the 70's, and with the sword/bored, we can take on even con^^^'s without any kiting. The second duo is her dirge and my assassin, which are currently in the 40s. Stuff tends to die rather rapidly with this combo as well.
I would think...anything that does melee/disease damage would be a great partner. SK/defiler/warlock would all be good choices.
