I duo a Shammy/Necro...unfortunately the Shammy doesn't get a pet :( ....Here's my experience thus far....I get much better exp killing solo mobs than I do in a well stacked group that takes kills non-stop group yellows. I don't completely understand why that is...ex. last night for 2 hours I moved four yellow bubs of exp killing solo snakes in Nek Forest. I ding and want to do beavers or owl bears so I start a group that was sick. Two shammys, cleric, SK, necro, and warrior. We did owl bears, guards, shrillers, you name it...was in the group for better part of 3 hours and I got 1 yellow bub. ???
Anyway, back to the question at hand...best duo...I'm a big believer in debuffs, like slow especially so that's why I picked a shammy, but I'm not sure just yet how their slows affect mobs dmg ration. At 24 it may not be a big deal, but at lvl 50 it can be all the difference. For that matter, I like my shammy/necro combo- good Debuffs, really good DOTs, it's just group mobs are difficult. If the shammy's got pets, there'd be your answer,imo. But they've down a good job balancing everyones strengths and weaknesses to the point that there's no clear cut, stand out combination.
Coordinating HO's is the key to your duo power. Things to consider about HO's are damage, consistency...i.e. my Shammy can do the same high powered HO every time, but the necro can't...sometime it seems the necro triggers a different HO and that can make a big difference in the DPS. I promise you this though, I can deal more damage by well coordinated HO's than some groups I see that are unorganized. Another thing to consider is you can't do HO's or anything if your getting hit for 300 dmg every round...Seems that EQ2, even though my DPS may be X, the mob's DPS is 5 to 10 times X.
Honestly, would seem to be the best option would be to come up with a duo combo and then add a cleric or an enchanter to every duo. Seperating the mobs and taken them down one at a time seems to be even more critical in EQ2 than EQ1. Anyway, that's my observation.
Syph - Mistmoore