The Lizard in the Amazing Spider-Man was disappointing. They didn't stay true to the character and the voice was kind of silly at times, CGI was meh, too. Dock Ock was more tragic and innocent than him in SM2. This Lizard was copying the Green Goblin "talking to yourself, conflicted, but still kinda evil". You never really felt bad for him. They actually cut the roles of his wife and kid from the movie (they had filmed scenes with them I believe). Why? I can only wonder.
I voted for Bane. Loki is a close second, just cause Hiddleson owns the role.
Bane hands down.
The one problem I had with The Avengers (and every other Whedon project for that matter) is that you never felt that the team was in danger. Loki was an awesome character, and Hiddleston was straight-up fantastic, but at no point was I like "Damn, Loki just might win this." With Bane, the dude beat the living hell out of Batman in the first act, and took over Gotham for almost the entire movie. That's a dangerous, menacing dude. Lizard was pretty meh. His main plan was pretty dumb, and he wasn't nearly as sympathetic as he was in the comics.
I have said multiple times Bane does not look menacing to me at all... he sort of look weak to me... because the guy playing the character was like 6'1'' or so... not really a massive guy his voice was pretty cool... but I look at Bane and feel no fear from his appearance nor his overall performance... the thing about Loki is... even though he does not look menacing at all either... the character has some pretty cool powers and he had to fight tougher opposition in The Avengers... even though they did mollywhoop his ass at the end ( The Hulk smashing )