Ah, that's good.
You really should give them a try. It's wonderful seeing all the similarities between it and
Halo. The Terminals are absolutely fascinating, as well. There's a small novel's worth of text in each game, I'm sure, and it's all incredibly interesting. The slow world building is fantastic, and you really get the sense that you're a pawn in a much larger game. Some of them are really bizarre and cryptic, too. Others are chilling. Some seem completely irreverent, but they all tie together in some way or another.
http://marathon.bungie.org/story/That website has transcripts of all the Terminals (though I'd recommend trying to find as many as you can in-game first), as well as analysis of various different plot points, characters, and mysteries. I'd really recommend going through some of those pages as you go through the game.