Recommended web technologies to rebuild a website [on hold]

I would like to get some guidance from experienced Web developers out there.

I started developing Web applications back in 2006 as a hobby, using CSS, JavaScript, some jQuery, server-side classic ASP and MSSQL.

Since then I didn't get a chance to grow in that field, learn new technologies/best practices to build a small-medium-scale Website, though my coding skills are good.

My website presents videos, data and statistics of sports. (http://ift.tt/16uh8kZ is a good example).

It has ~5,000 users, hundreds of thousands of records (players, teams, games etc.). Current database: MSSQL.

I want the best and fastest UX. (SPA? No "hard refreshes"? CSS3 transitions? What are the best practices for this? For example - how to render the DOM and only then fill in the data in the "dashboard" with as few HTTP requests as possible?)

I am a little overwhelmed with all the new frameworks - ASP.NET MVC, WebAPI, Angular, Backbone, MEAN Stack...

Which stack would you choose? Any recommended tutorials to learn from? Demos and examples?

Thanks a lot