The best band in Brazil is Legião Urbana

Wow! I'm surprised no one mentioned Seu Jorge 

https://www.youtube.com/watch?v=XwT2iiKeg1g

or if you want something a little more commercial Tribalistas

https://www.youtube.com/watch?v=gcr5ugrgIFs

Los Hermanos and Natiruts are also good

https://www.youtube.com/watch?v=9mXBTKKXCQU

https://www.youtube.com/watch?v=GT1rsW3SIlM

Capital Inicial, Pitty, Cássia Eller é muito bom também

Skank, Paulinho Moska, Paralamas do Sucesso, Maria Gadu. Ya mencionaron a Seu Jorge, que es excelente. Hay mucha música buena en Brasil

Listen Bandolins by Oswaldo Montenegro http://www.youtube.com/watch?v=hFn9egCWXsA