1 - "Never Die": Long, fast, and using several different instraments to keep you listening. This is by far my favorite, and the best of any of them, I think. Not only that, you can also imagine some uber-battle involving Ballos pumped full of steroids.
2 - "Ball of Ballos": Simply because the original pwns, and in guitar rifts it pwns more. If I could have it loop the rifts infinatly, rather than the... second half coming in, I'd listen to it for several hours.
3 - "Mimiga Vibe": 'cause Moonsong pwn'd, and the remixer did it justice.
It's a shame we couldn't replace the games music with the remix project; But even then, "Grass Stains" can burn the ears. It does mine. (Not to mention the main theme remix ["Cave Story"] isn't entirly complete; Listen through the original a few times, and you'll notice there's an extra portion of it you may or may not have heard before; This isn't in the remix.)