Yes, the speed stat helps both your attack rate and recovery rate after being attacked. For archers, the Reload Time portion of the bow/crossbow expertise skill gives a direct bonus to speed (I put the most skill points into Reload Time for my archer, and just a couple into damage, accuracy and point blank).
Each weapon should list any speed penalties or (sometimes) bonuses. Different weapon types do have different ranges of base speed penalties, but random stats can effect that. Knives and daggers have a base speed penalty of 2% while hammers are 8 or 9%.
I'm not sure exactly how the armour class is used in calculating how much damage you take when hit. Higher is better, but if there was not a big difference when selecting armour, I went more with the bonuses on the equipment than just considering the armour class alone.
