My favourite monsters in Diablo 3 would be the Mallet Lord and Boggart.
In Diablo 2, it would be the siege minions of Baal and maybe the oblivion knights.
Generally I like most of the undeads too.
What about you?
hmm…
D3 would be the seige mounts from Act 4… I suppose the undead handmaidens that vomit zombies would also rate high.
D2 would be the healers in Act3 with the corspe eater from Act 4 second
D1 is the acid beast
Most annoying mosters:
D3 the plague ghouls (leave behind poison gas)
D2 the undead soul flayers… I swear I killed them before they got near me… why do I still die…!!!
Also D2 before they patched it the Act 3 night lords… those meteors… if one was cast you needed at least a screen between you and the drop zone to avoid dying