I went to the trouble and clocked the attack speeds of all weapon types. Weapon material doesn't seem to make any difference (tested daedric, iron, skyforge steel, orcish).

Here's the result, listed as time per swing:

Dagger ___ | 0,75*Sword ____ | 0,9Waraxe ___ | 1,0Mace _____ | 1,1Greatsword | 1,1  Battleaxe  | 1,2  Warhammer  | 1,3Bow ______ | 2,6**

* Dagger speed usually clocked in between 7,3 and 8,0 seconds per 10 swings, so I decided on 7,5
** Bow speed for fully drawn string.

Artifacts may have completely different speeds altogether which will heavily influence dps. http://www.gamesas.com/topic/1340172-best-2h-weapon-the-longhammer/ for example is a two-handed orcish warhammer with a swing speed as fast as a one-handed waraxe, which gives it one of the highest dps in the entire game.

So I guess the rumours that Greatswords and Battleaxes have the same attack speed aren't true then?

Thank you, aroddo.

i was suprised to see that the mace swings as fast as a greatsword. In regards of dps for one-handed weapons the best choice would be the dagger and for two-handed weapons the warhammer.
not considering specialization perks, though.