tl;dr version:
tested steel-clad dorfs against each other, each weapon fought each other weapon 112 times (one-on-one) and won a number of battles as follows: Spear-256, Mace-220, Sword-310, Axe-273, Hammer-345, Pick-274
I have heard the conventional wisdom, but wanted to do some science for myself (unfortunately, no !!SCIENCE!! here). I tested weapons against armored opponents and hypothesized that the hammer would come out on top, as the wiki says. All testing was done in 34.07 in arena mode with male dorfs.
I set up 112 one-on-one battles of dorfs in all steel gear (helm, breastplate, greaves, gauntlets, high boots, shield and weapon) through copious use of macros. They were untrained in all skills. After the fighting had ceased, I recorded the number of dorfs still alive for that particular weapon and counted that as a win against the opposing weapon. There were a few cases of mutual death, so the end numbers don't always add up to 112. Anyway, here are the results, the weapons along the left were the winners and the top were losers. So, for example, the lower left number 61 indicates that, in 112 one-on-one battles of pick vs spear, the pick won 61 times. The totals on the right are victories per weapon, and the bottom are losses.
| Spear | Mace | Sword | Axe | Hammer | Pick | Total |
Spear | X | 63 | 45 | 49 | 48 | 51 | 256 |
Mace | 49 | X | 47 | 47 | 27 | 50 | 220 |
Sword | 67 | 64 | X | 58 | 58 | 63 | 310 |
Axe | 63 | 65 | 54 | X | 39 | 52 | 273 |
Hammer | 64 | 85 | 54 | 73 | X | 69 | 345 |
Pick | 61 | 62 | 49 | 60 | 42 | X | 274 |
Total | 304 | 339 | 249 | 287 | 214 | 285 | |
The hammer is still king, as expected, but other results were unexpected. For example, the mace was always outperformed, which was unexpected as I assumed it was a good blunt weapon. This is just preliminary research. I plan to expand the number of test subjects and test other variables (skill levels and materials on my radar right now). I'm open to suggestions as well. Also, if this type of thing has been done before and/or better, please let me down gently.
You can see the results here (as above, but better formatting):
https://docs.google.com/spreadsheet/ccc?key=0AhHKKKJZhFsrdDlpV3JJVGhOcnY1VGUtZ0o4bTVsX0EBonus results: On a whim, I checked on the wounds of the survivors. Most had zero or superficial injuries (bruised upper arm). About a fifth had more serious injuries to the arms or missing limbs. Very rarely did I find head/torso wounds.