Based on your post, it seems as though your mind is already made up and it's rhetorically suicidal to tell someone that their opinion is wrong. Furthermore, It's likely that anyone playing it today isn't going to to have as good an experience simply because ten years is a long time for spoilers to reach people. Considering that a lot of what made HaloCE work was the way it developed it's premise, this will invariably have an effect on newer players, especially if they've played other games in the series.
Anyway, it is of my opinion that asking "where the good bits are" misses the entire point of Halo's story, stories, and story telling for that matter. While some might not agree with this, Halo's story is enjoyable most likely because of it's unwavering initiative. Unlike practically every other game on the market, Halo managed to focus on it's central conflict rather than forcing the player to carry out a bunch of tedious side quests with little to no bearing on the overall progression of events. The game tries to make sure that the player knows exactly why the player is doing what they are doing. It's well paced and it's well plotted. It's not exact the deepest thing in the world, but it not only gives the game context, but it's more effective at making players care about the context.
Yes, the game does certainly borrow a lot of iconography and such, but it does this so that it doesn't have to explain what everything is and can instead focus on the progression of events. Contrast this with countless games that make their progression of events entirely out of borrowed or well understood icons.
From a purely critical perspective, Halo's story isn't actually all that good. In fact, I would dare say that the first one is the only game that actually achieves anything special in the terms discussed above. However, it's downright masterful compared to the rubbish that occurs in most video games.
. And word-wise, Starship Troopers.
