So yeah, what is it? Dual daggers, swords, axes, maces? Or a mixture of two of them?
Here's the deal with dual-wield:
Your left hand weapon determines the swinging speed for both, and right hand weapon hits twice during a dual-power attack.
Maces do the most raw damage, so if you want max DPS, you'll want a mace in your right hand. Maces are also the slowest, so you don't want one in your left hand. Since daggers don't get a bonus for Fortify One-handed enchants, you may want to avoid those later on in the game...
UNLESS
You have high backstab multipliers, in which case you may want to have dual daggers, as the multiplier during a power attack will take the x15 (or x30) for all 3 hits. With the right gear and circumstances (stealth), dual daggers will pwn nearly anything very, very quickly.
For non-stealth characters, you are best served with a sword in left hand and a mace in right hand for max DPS with better speed than 2 maces can offer. Also, the power attack animation bug with swords will come in handy for quickly staggering opponents and getting in a set-up shot for a dual power attack.
-Loth