Before Halo, there was Ringworld by Larry Niven. The funny thing is that, for all the awesomeness that is Halo, it pales in comparison to the size of the Ringworld. If you’re a science fiction fan, then you need to check out Ringworld. It’s quite literally a classic mastery of science fiction storytelling.
As to the rest of the Ringworld books…. meh, it depends. I liked the second one but after that, things kind of tapered off.