Lots of goodies from this - starters were kinda expected but will probably be the most talked about. Of course, for a lot of people they'll wait until the third stage evolutions are revealed until they choose their starter, but since the cover legendaries were also revealed, they can be included in the discussion.
My choice? Rowlet. Owl just happens to be my spirit animal, plus I've been waiting for a flying-type starter that isn't Charizard for ages. Now that I think about it, I've always chosen the bird if I could (I chose Torchic and Piplup in previous games). Finally, I'm currently at a 1/2/2 split with starter types, and if I went with grass once more it'll balance things out perfectly.
As for which version, as much as I like to Praise the Sun, I'm going with Moon. I decided to go with Moon even before this trailer launched because I always went with "the other one", as in Pearl, SoulSilver, White/2, Alpha Sapphire (the version that's always listed second). And it looks like I lucked out because I think bats are way more cooler than lions.
Artwork of starters and game box art: