Hmm... there are a lot of different aspects to weapons.
The scythe is the only AoE-Damage weapon, so if you want to have this, you have no choice.
The rapier ignores defense-properties (not just simply ones, it ignores PowerArmor, Lich Shield etc.) so if you want to pummel someone with a PowerArmor get a rapier.
The cleaver is slow, but has some style aspects, if you like FFVII get this weapon.
The Battlesign and the Pan arent that great... but they are fun, the sound of the Pan also is kinda funny.
The Longswords jump is kinda nice, while the broadsword basically is a normal sword.
The Hammer is the most effective TC-Weapon for dismantling the wither, since it has inherit Smite. Also getting Looting is easy.
The Battleaxe has the bonus of being able to mine wood. Similar to the Hammer you can get Luck (if you have at least 1) by choping wood.
I have never used the dagger... but how good can it be.
Also if you dont want an uber-weapon and just something to keep mobs at bay use an manyullyn-head shovel and enchant sharpness on it. You can easily get 5 hearts damage (so 10) and most shovel-materials are soft enough to not require much mining-speed. Unfortunatly Luck doesnt double as Looting and Fortune on a shovel (although I think TC doesnt tell you the damage anymore, it used to)
Here is the damage-bonus (added to the material-value) for all the weapons.
0 Hearts -> Mining-Tools (they normally dont show damage) have the reported 2 Hearts
0,5 Hearts -> Knife, Battlesign
1 Hearts -> Hammer, Rapier, Pan
2 Hearts -> Long-Sword, Broadsword, Battleaxe, Scythe, Cleaver
Also Rapiers ignore Armor and swing really fast (they seem to have a wider reach, but this might be visual due to there different animation).
Hammers have inherit Smite 2 (2-4 Bonusdamage to Undead).
Cleavers, Signs, Broadswords and Pans can Block.
The Battleaxe has a charge that will leap you a bit forward and gives you swiftness and haste.
Longsword and Rapier give 50% Bonusdamage when striking while sprinting.
Frying Pans have extra knockback and dazzle the target briefly.
The Cleaver has Beheading II, which gives more heads if you slay stuff.