The only weapon type I use in pretty much any game for semi-obvious reasons is Hidden Blade(s).
However, for Assassin's Creed III, the animations and combat fluidity of the Assassin Tomahawk was incredible.
So although I selected Tomahawks, I love Hidden Blades as well... Except for the fact that they're very slow in ACIII and Black Flag.
I have had A LOT of fun with the rope dart in the past two games.
For this one I went with the bow... it was close between the bow and the tomahawk really. The hidden blades were okay in this game, but Connor's animations begged for you to be brutal with a tomahawk and knife double wield. But it was the bow that I enjoyed most.
EDIT: However, my single favorite animation in the game is the counter-tool with a snare equipped. If you haven't discovered this brutal brutal kill, try it on your own.
“Force has no place where there is need of skill." Herodotus
I have had A LOT of fun with the rope dart in the past two games.
Was the rope dart even IN ACIV? (I kid... but not really)
“Force has no place where there is need of skill." Herodotus