From Python to..

Hi fellows!

It's been a while since I wanted to learn a new language and since I love Python (3.x please), I started to investigate on existing/similar/powerful other languages.

So far I can't choose among these:

go : syntax familiar enough to begin with easily
ruby : seems to be very popular and handy

Since I don't have plenty of time to learn I can only focus on one of them for a long time so I would like to make the best choice.

What would you tell me to chose? (why?)
Feel free to let me know about another one too!

Have a wonderful day