I have the first 3 in a special box set, had to be imported for my birthday (small country ftl). I really really want to read Ghosts of Onyx but that'll have to be imported too which is a pain in the ass.

You're right, The Flood (the game tie-in) was pretty pointless. While The Fall of Reach (my personal favourite), The First Strike, Ghosts of Onyx and I'm pretty sure Contact Harvest (the latest one coming out soonish, all about the first meeting with The Covenant at Harvest, apparently follows Avery Johnson) were written by Eric Nylund, a talented sci-fi author, The Flood was written by William C. Dietz, more of a Fantasy guy. The thing is, Nylund had an easier job because people are going to enjoy reading the story they don't know more than reading about the game they've played, though The Flood did tell about what all the marines were doing on Installation 04. Dietz drew the short straw really, though that's not to say Nylund's not the better man for the job.

I also recommend the books. While The Flood doesn't contribute anything to the storyline that you won't already know, The Fall of Reach gives a LOT of background and I don't know how I ever followed Halo 1 without reading it. It also makes the Master Chief a cooler character and gives an otherwise bland sci-fi storyline unique background. The First Strike is less integral to the story and tells about what MC and Cortana got up to between the first and second games. It was essentially owning a Covenant fleet and some ridiculously cool sniping (with one hand while hanging from a Banshee at full speed.) From what I've heard, The Ghosts of Onyx provides a lot of insight as well.

These books are what make the Halo story not average and why a movie, particularly one featuring some of the other kickass Spartans like Linda and Kelly, would be sweet.

Those of you who haven't seen the live action Arms-Race shorts need to Youtube them now. They are incredibly, incredibly, incredibly cool and show how the Chief made it to Earth in time for Halo 3.