Which Is Your Worst Performing Google AdSense Unit?

A WebmasterWorld thread is bashing the video Google AdSense unit. Many AdSense publishers call this unit earn nothing or next to nothing with this unit. The question is, is the forum bias or is it true?

Please do comment below but also take our poll. Which Google AdSense unit is the worst performing unit you are running?

I left out referrals because those have been discontinued. Looking forward to the responses.

Forum discussion at WebmasterWorld.