Learning languages: given the fact I can only devote limited time for learning a second language, which European language would you suggest I learn from a pragmatic point of view?

You have to take in consideration the time you have.I have learned french,russian and spanish.French,spanish and italian are alike and given that french is the hardest i would recommend learning it then you can understand the other two on a very basic level (altough understanding italian would be harder since it differs more from french than spanish). German and russian are still very common and useful.If your first language is english i think it will be easier for you to learn german.Mine isnt and russian as well as french were easier for me.Depends on the time and the effort you are gonna put in it.

I would have to recommend French or Spanish. But given you have mix of Germanic, Latin and Scandenavian languages throughout Europe (and I'm omitting the Russian ones) you would have to narrow it down a bit. But I would definitely recommend a Latin based language for its beauty, future and present "usefulness" and deep history.

Pragmatic suggests easiest to me so I suggest Italian as its pronunciation and spelling are so closely linked as to exclude redundancy.

The question is really not that difficult. Spanish - if you are going to a country where people speak Spanish or you have interest in people/culture of any Spanish-speaking country. French - if you are going to a country where people speak French or you have interest in people/culture of any French-speaking country. Italian - if you are going to... and so on. In sum, follow your passion, and not only statistics.

If you have a limited amount of time and want to be practical, Spanish is probably the best choice. Although the Spanish verb system is complex and can take a long time to learn, Spanish is probably the easiest European language for a native speaker of English to pick up, especially with a limited amount of time. Keep in mind that if you have a limited amount of time, you are probably not going to make a ton of progress in any language you try.