The removable cowl Batman was a great figure with a cool head sculpt. He was only produced the first couple of years. Another favorite was Green Arrow, who many consider the best Mego produced.
Here are some more favorites. I think readers of this blog will recognize who they are. Megos were a great representation of super heroes at the time.
I just recently picked up a nice Superman at a toy show a couple of weeks ago. Here he is with another classic Mego who actually had super powers, if you consider drawing chicks with a snap of the fingers a super power.