This sounds horrible dude. The guitar parts don't match at all, and that fact that they're hard pans makes it even more obvious, sometimes there are spans of 30 seconds with the guitar only coming out of one side. The toms really boomy, have all kinds of overtones and are clipping in some parts. The guitar tone is thin and hollow, partially because it doesn't have a matching bass part to thicken it up, but it is not a good guitar tone even when the bass is not playing. The bass guitar is too loud in relation to the guitars. I don't even know where to tell you to start with fixing this; it's really a mess and myspace compression I'm sure isn't helping. Post up a higher quality link using dropbox and people will be able to help you better.
Also: monitors with a flat response don't wouldn't be a reason for a boomy mix, monitors that lack bass make for a boomy mix because you don't know how to mix the low end
