Perhaps this Triceratops skull?
Estimated value: $125,000 - $175,000
Or maybe this Tyrannosaurus skull?
Estimated value: $250,000 - $300,000
Seriously though, any kind of dinosaur skull would be awesome...and two would be twice as awesome. We could put them on our heads and have epic dinosaur battles, scare little children, and win all the Halloween costume contests!