In my humble opinion and speaking not as a Brazilian but as an American some jobs should require English fluency as a condition of employement and as a part of their job discription: aircraft pilots (required by the International Civil Aviation Organization), persons working in the tourism industry, Customs Officials, and anyone who has routine contacts with English speakers, etcetera. All other industries should encourage fluency in at least one language, other than Portuguese, and reward employees who are fuent.
With that being said I feel that any citizen of any country should try to be at least partially bilingual. By partially bilingual I mean a person should try to have a minimal knowledge of the spoken language, so that he or she has the ability to verbally communicate at least on a basic level.
Being bilingual or trilingual will be more important as the relative size of the world continues to shrink on a daily basis, therefore all members of this site should try to improve their skills, because you never know what opportunities may present themselves.