Ben
Loved Ben on first seasons. But lets face it - our cute nice Ben died. And that other one was horrible. Whiny prick. And didn't even redeem himself at the end.
They shouldn't have kill real Ben. He was a good character. They should have bring him to life somehow.
And I loved how they never explained why dead Ben aged like everyone else. Remember that he died as small teen. Instead of having same teen play Ben - they cast adult actor.