Another vote for simplicity:

 Your game is about an excavation? you name it the dig and put a hole in the cover.

The Secret of Monkey Island. I can look at the Dig box for like two seconds and take in the whole thing, while there’s a lot new to see in MI with every passing of the eye.

Voting for Secret of Monkey Island, it radiates adventure essence.

The Dig looks just more plain than possessing that minimalist - "less is more" quality.

Secret of Monkey Island

I like both covers but The Dig is my choice.

Monkey Island!!!

Monkey Island - it's vibrant and seems exciting.

The Dig cover gets my vote.

The Dig on this one but neither are among the best for me.

Ah, we are in round 2 now?

Voting for Secret of Monkey Island, it radiates adventure essence.

Yeah, exactly that. Few covers do this as well as Monkey Island 1, in fact.
The painting is so perfectly composed, everything is so nicely balanced, it just feels so right. And is a great piece of art.

So even though The Dig is decent, the minimalist style is effective, and the logo is very slick – I can’t vote for anything other than MI.
Really, the only thing in this contest that could beat it for me is probably MI2.