First, I like the riffs and the arrangement, very nice! You've got my headbanging!
With regards to the mix it is lacking a lot of mids and the drums don't sound particularly 3D.
Guitars: Here's what I suggest, start messing around with the mids on your guitar from around 700hz to 4khz (it might sound harsh at first but take an ear break and come back to it later, also compare it with other mixing, you'll notice they have plenty of mids around that frequency band).
Feed the guitars to a reverb bus and get them sounding bigger, just something like a medium sized room, feed them in to the bus until you start to notice, then pull back the feed by around 3-6dB. You always find you overkill at first! The key is to do something to the point where YOU don't notice it basically, but it's still there, yeah?
Drums: Again, with the drums, they don't sound very big or 3D! Reverb is your friend. Use a room style reverb like what I suggested with the guitars and then you can use longer reverbs on the snare on the toms.
Output: I'd take a look at your overall mix from the output perspective, perhaps look at the mids again as I mentioned with the guitars.
Here's an example of some drums I worked on:
http://snd.sc/11Bw7di
hugs
