You guys are forgetting one of the most important languages in the world now, and for the future - Portuguese !
Once you become fluent in Portuguese you get Spanish practically for free, at in terms of understanding it. The grammar, vocabulary and overall structure between Portuguese and Spanish is about 90%. Not kidding here.
In terms of importance as a major language of the world, there are many, many reasons. Portuguese is spoken officially by 280 million people, on 5 continents, and it is 5th most spoken language in the world! Portuguese is spoken officially in: Portugal (inc. Azores and Madeira), Brazil, Angola, Mozambique, Guinea-Bissau, Cape Verde, San Tome and Principe Islands, East Timor, Macau, Equatorial Guinea.
Brazil has at moment the 5th strongest economy in the world! Brazil is a HUGE country which occupies roughly 50% of the land area in South America. It is an extremely beautiful, and natural resource rich country which has an abundance of: oil, natural gas, gold, silver, coffee, sugar, and is a world leader in aerospace, telecommunications, computer technology, and a major producer/exporter of important consumer goods and foods. 51% of all the speakers in South America speaks Portuguese.
Portuguese is he 3rd most spoken European language in the world, the 3rd most spoken in the Americas, and the 1st most spoken language in the Southern Hemisphere.
Portuguese is the language of many important global organizations including: Mercosur, Latin American Union, European Union, African Union, and CPLP (Community of Portuguese Speaking Countries - which even have their own Olympic Games).
Portuguese is spoken in 6 African countries, whereby Angola an Mozambique have the top 5 strongest African economies in Africa. Both of these countries have abundant natural resources including: oil, natural gas, gold, diamonds, silver, sugar, coffee, etc.
The main trading partners of all of the Portuguese speaking nations, especially Brazil, Angola, Portugal, Mozambique, are: China, United States, India, Canada, and Australia among many others. As such, the Portuguese language is well positioned as an important language of the 21st century and beyond world economy.
Portuguese is currently being taught as a preferred 2d language in many countries in the world including: Japan, China, Argentina, Uruguay, Paraguay, Venezuela, South Africa, Namibia, Senegal, France, Spain, Luxembourg, Andorra, etc.
There are huge Portuguese immigrant communities all over the world in the following countries: Canada, United States, Venezuela, England, France, Germany, Luxembourg, Andorra, Namibia, South Africa, Israel, Australia, India, China, Japan, etc.
And Portuguese is soon to become the 7th official language of the United Nations.
All of the above reasons given are proof positive of why fluency, or even basic conversational Portuguese is a huge asset in today's globalized world.
And most importantly, Portuguese is a very beautiful and expressive romance language, which is becoming more and more important everyday! And knowing this wonderful language means that you will be able to communicate with millions of Portuguese speakers all over the world. Furthermore, knowledge of the Portuguese language will give you a huge advantage over everyone else if you ever visit a Spanish speaking country!