The Marathon OST, sadly, isn't on any of those. :( Best just to find a playlist on youtube [url=http://www.youtube.com/watch?v=jjC1ELR6Rv4&playnext=1&list=PLDA493090201B3116&feature=results_main]like this one[/url] and then using a youtube-to-mp3 converter (google search it). That's pretty much the only way to get them onto your computer, although if you download the Marathon game from Aleph One (it's free and Bungie allows/supports it) from [url=http://source.bungie.org/]here[/url], all the tracks from the soundtrack are in the game's files.