[Aerich]

You've got pretty good ones so far. I look at three things when assessing weapon strength: magical '+', special bonuses (like the Bow of Sseth's extra attack per round and tiny initiative modifier) and secondary effects (poison, chance to stun, chance to petrify, elemental damage or other extra damage).

Generally, I use the weapon with the best + and/or damage potential, unless I figure that the special or secondary effects give a greater advantage (as they often do, especially when using a high level warrior that can hit just about anything without the addition to Thac0 of a high + weapon). I am fond of stunning weapons.

You are carrying good weapons, probably the best you could be for that stage of the game, although I might be inclined to use the Bow of Sseth instead of the Black Bow. It's kind of like using a machine gun over a sniper rifle - less chance to hit with an individual round, but a superior rate of fire.

And yes, some weapons are suited for specific purposes - look to their descriptions, and consider the monsters you will be fighting. Don't forget to factor in possible monster resistances to slashing, piercing, bludgeoning and missile weapons. For obvious reasons, I prefer flaming weapons when fighting trolls (you can buy the greatsword Trollslayer from Conlan, which is simply awesome against trolls). You will also enjoy the Three White Doves (anti-undead mace) when you get to HoW.