All that up there can be yours for $150 when Halo: Reach comes out later this year. That stuff comes with the Legendary Edition. The chunk of bric-brac front and center is 10 inches tall and "more than ten pounds". In that weight class, it should hold down your papers with aplomb. You also get an "exclusive Spartan armor effect" during multiplayer games so everyone knows you're the kind of guy who has at home a more-than-ten-pound tchotchke.
If you're not quite so committed to the upcoming Master Chief-less Halo, maybe the Limited Edition is more your speed. In that case, you just get the box and the story-related printed material in the background. And since you have only paid $80, you can use the $70 you spent to buy commemorative plates or something.
Everyone else only gets the game itself. A Halo: Reach multiplayer beta goes live on May 3rd to give you more insight into that part of the game's collectors' editions.