Frostlord
Super Freak
I think more people on the street would recognize even Mystique before they would "major" Justice Leaguers who are big in the comics but have no mass appeal. Nothing beats DC's top 2, but Marvel is more recognizable overall. I love em all though!
Aside from popularity I also think the last 3 Marvel PFs also suffered from just not being as good as the last/first 3 DC PFs. You can't beat Batman, period, but SW and Spider-Woman just aren't as good as the other sculpts. And Hawkeye actually does look great, but not having a switch out part EX is the only reason it's ES isn't at least 500. They could have even just painted the EX bow and arrows brown and it would have probably been 500. Throw in Ant-Man and you would have had a winner.
couldn't have said it better myself