I used to have comprehensive knowledge of the Halo universe before they went with the Ancient Humanity angle, that's where I lost interest. I still have plenty of the novels and the first visual encyclopedia they released.
I really disliked that stuff when I read about it. I guess it was done in order to make the Halo universe a little less cliche to other science fiction media that handled similar themes (can't exactly recall which ones at the moment but it has been used before; humanity being the inheritors of the power/technology from some uber race), and in that I applaud the writers, but to the whole story about humanity's ancestors (various branches of humanity if I recall) having an interstellar empire that fought the Forerunners, explaining where the Flood came from.
Yeah at some point they completely lost me despite that I consider myself a serious science fiction fan.
It didn't help that I had also stopped playing the Halo games around Halo 4.
I am glad that I was never as invested in it as I am in the Fallout franchise and Star Trek.
Favorite science fiction? Damn, I have seen, read, and played a lot, and yet I feel I really have not done much at the same time.
Well I have read several books by Heinlein such as The Moon is a harsh mistress, Stranger in a strange land, Starship Troopers, the Door into Summer, Citizen of the Galaxy.
Books by Niven such as his Known Space books such as the Neutron Star short story collection, Tales of Known Space, the Ringworld books, the Man/Kzin Wars. Non Known Space such as Lucifer's Hammer, Footfall, The More in God's Eye, A world out of time.
Two books by Frederick Pohl such as Gateway and The Coming of the Quantum Cats (I liked the last a lot)
A fire upon the deep, A deepness in the sky, and Across Realtime by Vernor Vinge.
Several of the Revelation Space books by Alistar Reynolds and Century Rain (I warn you, these are long reads)
I also read a lot of Star Trek books but I would not consider those to be serious science fiction, and you would really have to be a fan of the franchise and have some really deep knowledge about the shows and the movies.
In general I liked a lot of Peter David's stuff, in particular his New Frontier series which take place in its own corner of the galaxy.
Television.
Hmm, well I used to be a big Star Trek fans before that fell into decline during Voyager and Enterprise.
I watched a lot of the old shows like old Buck Rogers in the 25th Century and old Battlestar Galactica, but those are mostly entertaining from a campy point of view.
Seven Days was pretty good but it is not serious science fiction.
Sliders had its up and downs before becoming really bad, again not really science fiction.
Stargate SG-1 was fun but suffers the same fate as Star Trek. The spin offs were weaker than the original.
Recently I have watched several episodes of the Expanse, a series based on a book series that looks interesting. Definitely more serious about the science part.