As a pioneer of video game music, Metroid has always been a favourite of remixers. Super Metroid, the second Metroid sequel, was a masterpiece of video game music, and many of its tunes were woven into to moody, if not as revolutionary, scores in the Metroid Prime Trilogy. It's no surprise that Super Metroid was the first game to be remixed as a complete album (Relics of the Chozo) on OCRemix.org.
Anyway, Harmony of a Hunter is the latest full-length album remix of Metroid music, and it's worth checking out. I haven't listened to the whole thing yet, but so far, it's lots of orchestral goodness. The creators promise that Harmony of a Hunter "includes music from the original NES Metroid through Metroid: Other M for the Nintendo Wii. The album features a diverse range of talented individuals covering a variety of genres which we hope will appeal to many musical tastes."
For those interested in the technical and theoretical side of video game music, I also highly recommend Game Sound by Karen Collins, which discusses the composition of the original Metroid score by Hirokazu Tanaka.