One thing to consider with Dual Wielding is (so far as I can tell) damage bonuses (+X melee/magic) are counted twice, once for each weapon. With two weapons with good enchants/charms/other bonuses of this nature the damage you deal out can be quite substancial. By the end I was dealing 420 to 503 normal damage and 248 to 273 magic damage in melee, and I had not really pushed the stats that up damage and both swords still had a charm slot.

Edit (Math):

Dual Wielding 13: 25% / 50%
Strength: 52 * .5 = 26%
Intelligence: 42 * 1 = 42%
Right Hand: 46 to 77 + 27 (+27)
Left Hand: 27 to 45 + 59 (18 to 30 + 27)

Here are some possible formulae for max normal damage.

Formula 1: ((77 + 27) * 1.25 + (45 + 59) * 1.5) * 1.26 = 326.34
Formula 2: ((77 * 1.25 + 45 * 1.5) + 2 * (27 + 59)) * 1.26 = 389.025
Formula 3: ((77 + 27 + 59) * 1.25 + (45 + 59 + 27) * 1.5) * 1.26 = 470.296
Formula 4: ((77 * 1.25 + (45 + (59 + 27) * 2) * 1.5) * 1.26 = 497.385

The real value is higher still (by about 5.6), but the fouth formula is fairly close. It would be intersting to see how the numbers for two handed weapons stack up, if someone cares to post them.