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My impression from beta streams and such is that 2h vs. dual seems to be pretty balanced.
So I will be making the choice just on drops.
If I find a good 2h (go 2h) or a good 1h (go shield) or 2 equally good 1h (go dual).
If they don't differ that much in power I will choose 2h or shield for style over dual.

A flat comparison of DPS is "easy."

For convenience sake, lets use a Monk who uses Hundred Fists unruned and Lashing Kick unruned on single targets to start. Using Monk because he has no non-item/skill Spirit regen.

Given the current ratios of rare weapons at 60 (which presumably scales true at all levels) according to d3db.com, the base damage of a Daibo is 35.93% higher, so I'll use 100 dps fist and 135.9 dps daibo. Fists have a speed of 1.4 APS, and when dual wielding, you have 1.61 after the bonus. Or in other words, you have 115 DPS. Just based on these values, the Daibo is doing 18.2% higher DPS.

You could calculate the damage of each skill or DPS of each skill, however, you have to take into account the Spirit regen, which is:
Fists: 1.61 * 6 = 9.66/s
Daibo: 1.1 * 6 = 6.6/s

In other words, on average after every 30 / [Spirit Regen] seconds, you can perform 1 Lashing Kick.
Fists: 3.11s
Daibo: 4.55s

It will take 1 / APS to actually perform the Ability, so we can add that time to the previous to find the average time of the rotation:
Fists: 3.727s
Daibo: 5.45s

For the end practical dps for Fists, you are doing 3.11s at 140% WD, and 1 instance of 200% for every 3.727s. Add the two damage values and divide by the time to get the overall dps:
Fists: 100 DPS / 1.4 APS = 71.4 Avg Dmg
Daibo: 135.9 DPS / 1.1 APS = 123.5 Avg Dmg
Fists: (3.11 * 115 * 1.4) + (71.4 * 2) = 172.5 DPS
Daibo: (4.55 * 135.9 * 1.4) + (123.5 * 2) = 203.9 DPS

So as a result, Daibo is doing 18.2% more dps, which is exactly what you expect.

The calculations get way more interesting when you add in additional sources of passive spirit regen, multiple targets, skill procs, and rotations beyond 2 skills. But yes, the more important point to be made is that it strongly depends on skill selection. The more passive spirit regen, the better the Daibo will be in using Spenders, while 1H/S and DW will remain the safer option due to requiring less time

Edit: Corrections made

That blog is outdated.
http://www.diablofans.com/blizz-tracker/topic/219255-main-hand-damage/

This is an awesome point. Using a 2 hander can nullify your need for resource generation under some circumstances because of the higher damage per resource point and lower rate of fire. It's a game changer.

It changes very little... there are still going to be circumstances where you must use your ability N times regardless of the strength of your weapon simply due to the number of targets and how spread out they may be. Also, by using a spender as all attacks, you remove the ability to reserve your resources for more critical moments.

There's an 18% difference in equal level 2h and dual-weilding DPS. DW results in a 15% increased resource regeneration however, which is not immediately quantified in terms of DPS or survivability benefits.