Well, David is definitely right. The vocals are sunk a fair bit back. What kind of percussion are you adding? If you are adding a kit, I would suggest adding a bass, and actually pulling a little bit of lowout of the guitar, which would balance out the mix really nice. If you are just adding hand drums or something, then just a little eq(some bottom end mud there) and you should be fine. The lead guitar isn't sitting very nice either. When it first comes in, it is overpowering, almost knocked me outta my chair. It starts to settle back in a bit, but it should be dealt with too.
Otherwise, the actually sound quality of everythign recorded is pretty nice!
Simon