With the Hugo nominating deadlines just around the corner, I'm sharing my ballot (incomplete in plenty of areas), though while I hope you'll consider the various fancasts and related works I'm nominating, I'd otherwise recommend the Hugo Spreadsheet of Doom, Abigail Nussbaum's nominations, and ForestOfGlory's short fiction recommendations at LadyBusiness, since they're all more useful than mine, especially if you're looking for excellent short fiction to read.
Best Novel -
Underground Railroad, Everfair.
I have 2 Best Novel nominations. Underground Railroad is fantastic, deserves to win any awards it's eligible for, and while it's marketed as a mainstream novel, is also very comfortably a genre novel. Don't believe the nonsense that "the speculative element is the literalized Underground Railroad". This book takes various approaches that White America has attempted towards African Americans (genocide, scientific exploitation, etc), and imagines their implementation on grand scales, solidly in the tradition of many science fiction novels. Everfair is ambitious, made me cry in places, and does an excellent job of differentiating between the narrative perspective and the various sensibilities of characters in the novel. I'd recommend this review from Strange Horizons as well as Abigail Nussbaum's quick review which notes some of the weaknesses of the scattershot approach the novel takes to covering its grand scale.
The next-best 2016 books I read were Obelisk Gate, Wall of Storms, and Ninefox Gambit. I don't want to nominate book 2 of a series which I didn't think was as good as book 1 (which describes both Obelisk Gate and Wall of Storms), and I think Ninefox Gambit is a good Space Opera, but that was the extent of my reaction to it, and again I don't want to nominate "a good Space Opera". I bounced hard off the narrative voice in All the Birds in the Sky, but if you're engaged by the first few chapters, I've heard good things. I wish I'd made it to Cixin Liu's Death's End, Indra Das's The Devourers, The Winged Histories by Sofia Samatar, and Lavie Tidhar's Central Station, but I didn't. (If you're looking for good novels, I'd also recommend checking out the Shadow Clarke Award discussions and reviews)
Best Novella -
Ballad of Black Tom, The Taste of Honey, Bethany.
I didn't read many novellas this year, but Victor LaValle's response to Lovecraft's Horror at Red Hook, Kai Ashante Wilson's heartbreaking The Taste of Honey (jeebus, I'm gonna read everything by Wilson ever), and Adam Roberts' Bethany were all excellent.
I didn't read any memorable Novelettes last year, sorry.
Best Short Story
(Again, go see ForestOfGlory's recommendations, and Abigail Nussbaum's, and check the Hugo Awards eligibility spreadsheet)
One Way Out (Ethan Robinson), Can't Beat Em (Nalo Hopkinson), Congruence (Jehanzeb Dar), The Banshee Behind Beamon's Bakery (Khaalidah Muhammad-Ali)
I really liked Ethan's self-published blog post, reviewed Congruence as part of my review of Islamicates vol 1 at Strange Horizons, and the other two just keep sticking in my head. All worth a read.
Best Related Work -
#BlackSpecFic: the Fireside Fiction Report, Speculative Blackness, Modern Masters of Science Fiction: Octavia E Butler, Food and Horror, Dragonlance Reread
The #BlackSpecFic report from Fireside is an essential read and look at how our short story ecosystem is failing black authors. Andre Carrington's Speculative Blackness was incredibly thought-provoking, and Gerry Canavan's book about Octavia E Butler gave great insight into both the author and her works. I really enjoyed OJ Cade's Food and Horror series at BookSmugglers - whenever it dropped, I set aside time to read each post, and I'm waiting for a good opportunity to reread and savor the whole series. I also quite liked Mahvesh & Jared's Dragonlance reread, which threaded the needle of both celebrating why this was such a beloved and essential series while also acknowledging it's weaknesses.
I'm nominating Clippng's Splendor and Misery for Best Dramatic Presentation, Short Form, because it's a really fascinating album with a good story about space travel, but otherwise I have no opinions on dramatic presentations, editors, artists or graphic novels. Sorry.
Edit - I'm nominating Olalekan Jeyifous based on Cecily Kane's recommendation, because my goodness those cityscapes :)
Best Semiprozine -
Yes, I'm a Strange Horizons fanboy who enjoys their reviews too much. They're pointed at my (fascinated by academia, without being well-read or formally trained), sorry.
Best Fanzine -
Nerds of a Feather, Lady Business
I'm of the opinion that a fanzine should be a group effort, and these are the two group efforts I really enjoy.
Best Fancast -
Cabbages & Kings, Fangirl Happy Hour, Storyological, Flash Forward, Midnight in Karachi.
I overanalyzed fancast a while ago.
Best Fan Writer -
Abigail Nussbaum, Megan AM, Vajra Chandresekara, Charles Payseur
Again, I'm pretty sure I overanalyzed these a while back.
Edit: Filling this out with O. Westin of @Microsff
It seems odd to me that Jennifer Brissett is eligible for the Campbell Award for Best New Writer, but I do not understand Hugo eligibility rules. I dare you to check out her bibliography & tell me she's not deserving of an award.
I'm mostly not nominating in Best Series because a) I haven't been following many eligible series, and b) I think that Best Series is a silly category that may track the market but is really hard to participate in beyond nominating your favorite series if you're already following one. But Kate Elliott's Court of Fives series is in the same world as her Crossroads trilogy and ongoing Black Wolves series, so I'm nominating it because I've loved many of those. And because this is one of many examples of why the series category is dumb.