Since nobody has represented two weapons worthy of some attention, I will.
Short Sword of Mask +5
15% chance to drain 1 level each hit.
15% chance to entangle the opponent for 24 seconds, no save.
THAC0: +5
Damage: 1d6+5
Damage type: Piercing
and
Answerer +4 (longsword)
Each hit lowers opponents magic resistance by 15%
Each hit applies a -2 penalty to opponents AC
THAC0: +4
Damage: 1d8+4
Speed Factor: 9 (This is the bad part 
)
Both are very nice since none of the abilities are resistable. While they may not be the best weapons offensively, they cripple the enemy as their abilities go off. When playing with a party, I almost always have one person using the answerer in the larger enemy battles... 3 hits and the target looses 6 ac, which means they and everyone else will hit a whole lot more. Pretty potent in my eyes.
The sword of mask is quite nasty as well. Its level drain ability is percentage based, so you don't have to worry about savings throws... Well the sword of mask isn't super potent, but its a nice alternative, and its fairly easy to get. Just buy it from the merchant priest ontop of watcher's keep, and kill the lich in Sendai's enclave. Most of the better 1handers are ones you have to delve deep into watchers keep, as well as the plot of ToB to get...
Since this is Not just about specific weapons it seems, rather what group of weapons to go for. Assuming you are a fighter, and want to fully specialize in the weapons types you are using, you should be able to have 2 groups at grand master... and of course if you are say a paladin, you can have even more types available since you can only reach specialized.
So its really more about combinations. Using Answerer for a hit or two then switching to say Foebane would work well, and you would have the ability to use all the other longswords and bastard swords you find in your career. I think Axe would be a good group for you to take, since there are umm 5 throwing axes (+2 thrower, Hangard's Axe +2, Rifthome Axe+3, Azuredge, and K'logorath +4) as well as the axe of the Unyielding. Azuredge can instantly destroy undead, K'logorath is a awesome thrower with a save vs death or knockdown and extra damage effect, and of course the axe of the unyielding is a very nice weapon as well...
I hope some of this made sense... Doesn't to me [img]tongue.gif[/img]
-Eldoran