for me, it is probably the Triple X because it is simple but effective and hits a lot close range. I know lots of the weapons hit a lot close range but the Triple X is unlocked at quite a low level and all of the other amazing weapons are unlocked at about level 40+
I like the throwing knife or the tomahawk just because they bounce and no matter the speed the damage is the same. The weapon I use the most is the basic unlimited grenade. The repeater can cause a good amount of damage if it's a direct hit, but can mess up the terrain if you mess.
I like the Mortar because if you use it right it takes away alot of their health.
I like the mortar aswell but it is really bouncy which can get on my nerves a bit sometimes when you directly hit the egg and the flare flies of some other direction...