Sounds great! Would it be possible for you to upload a less-compressed version of the same mix? I have a suspicion that your drums would sound a LOT better with less compression, since it's taking a lot of the sparkle and "air" out of the snare and cymbals.
My own preference would be for a little more gain on the lead guitars, but that's just my own warped sense of things. Most folks would probably disagree with me. The rhythm guitars sound fantastic--don't change a thing.
As for improving the drums, besides using a better, deeper kick sample, I think you might want to have the cymbals just slightly higher in the mix. Not a lot, though. Also, I don't do PC recording (still hardware-based) and so I don't know all the available shit with plug-ins and such, but is there a groove function you can run on the drums? Your cymbals already have a nice sense of groove, but introducing a slight bit of dynamic variety on the kick would help make it sound less machine-like.