What is the best language to learn at this moment?

I used to write html and was in a magazine way back in 1995. After joining the service and doing other things for the last several years, I have forgotten most of what I learned during that time period. However, I have constantly kept up to date with the user-facing side of technology. I would like to learn a programming language. What is the best language to learn, and in what way can I help and contribute in that language in 2013 and beyond? I used to spend hours coding html back in the day when I was a kid, and those were the best times of my life...I seem to have lost it, but the fire still burns.

If you are looking to do web, learn Javascript the future of the web is moving to platforms that expose themselves as JSON services and Javascript/HTML application consuming those services to create workflows ontop of a mixture of those platforms. Javascript has become an essential language to the future of the web.

Python or Ruby. I know Go and Node.JS are trendy right now but still i would recommend Python or Ruby

You're mentioning HTML so it seems that you're more into web. I'd recommend: Python, Ruby and Javascript.

Some would say Python or Ruby. I suggest both. Once you learn one, it's very easy to pick up the other. As much as their similar, their library support and tools make them useful for different purposes as much as the same purposes. To go into a little detail, if you're building a website with some offline or non-web aspects, go with Python. If what you want to build is entirely on the web, go with Ruby on Rails / Sinatra. With these skills, you can build awesome web apps and tap into the huge library support of Python for non-web related issues.

Finally, you just have to learn Javascript if you want to dive into web. Start with pure Javascript, some jQuery and pick a library (Backbone, Ember etc...) and learn it.

I'm surprised almost no one recommend php even though it powers almost all of the web, and is the easiest to setup. I strongly recommend php, javascript and css. And everything else will just follow.