There's also alot of Heinlein. I do like Heinlein but that's still silly. Citizen of the Galaxy is the only one of those I haven't read but I wouldn't be surprised if it was the one I ended up liking best. Stranger in a Strange Land and Starship Troopers are very overrated but are made more interesting by the fact that he wrote them both at once.
It's funny that there are three Hubbard books and one of them is a Mission Earth book. That series is despised. Fear is supposed to be his best book (I have it and will read it some day), Battlefield Earth is widely mocked but at least it has non-Scientologist fans.
The one Hubbard I've read was Final Blackout, which is supposed to be one of his best and one that still has non-Scientologist fans. It's a military SF, post-apocalyptic book. I did not like it overall but parts of it are okay. Reading it now you know that Hubbard sees himself in his iron-fisted hero and it's disturbing. His other best remembered book is Typewriter in the Sky, a humorous novel about a guy who gets trapped in a story his friend is writing (or something like that). I have it in the same book as Fear so I'll probably read that too. I think the only other one SF fans talk about on its own merits is To the Stars (aka Return to Tomorrow). It deals with time dilation in space travel, and it was unusual for Hubbard to write stories that revolve around actual science. It's near the time where he stopped writing fiction (until the 80s) and I think it's supposed to have some Diantetics inspired stuff in it.
I recently learned that Hubbard claimed to have co-written some Hollywood movies, including Stagecoach, but he was only employed in Hollywood for a very brief time and there is no evidence for this claim.