Ask HN: What new web tech would you hang your hat on for 2016?

I used to prototype/develop cutting-edge web experiments a few years back (when WebAudio, WebSockets, NodeJS, LocalStorage, etc. were just taking shape), but I know a lot has changed (with hundreds of competing javascript libraries).

I figure HN is a pretty great forum for a question like this, so what do you think? What libraries/approaches seem like the best places to focus for building new and experimental web apps and services of the future?

Some potential starters:

- What's the best core js library(s) (it used to be jQuery, but there seems to be a lot of competition now)?

- What page model is best (the buzz used to be "single page applications" but not sure that still rings true)?

- What backend structure looks to be a solid foundation for most things (Node and MongoDB on solid state drives used to be all the talk)?

- What new HTML5+ web technologies look most promising (used to be WebSockets, WebAudio, LocalStorage, and getUserMedia)?

Thanks in advance, and I hope for a fun (friendly) discussion!