Slytherin, I think. There's too much apathy I see to really take Gryffindor honestly, but Gryffindor and Slytherin, as houses, are so intertwined it's sometimes hard to tell them apart.
So a very strong Slytherdor feel, but I think just a edge more Slytherin than Gryffindor. (No one ever said Slytherin's couldn't be adventurous)