Yes. When choosing a dictionary it is important to bear in mind the reasons for such a choice. Do you need a dictionary for travelling, for studying, a dictionary of the language, a dictionary of the use of the language, or a dictionary of slang?
Brazilian Portuguese and European Portuguese may vary in pronunciation and use of some vocabulary. Take this into account when buying your dictionary.
If you are a Beginner or Intermediate student, a bilingual dictionary would suit you while a monolingual dictionary would be more appropriate for an Advanced student.
We’d recommend a dictionary that includes the items listed below (or at least most of them):
• the pronunciation (easy to understand);
• the etymology (origin of word);
• the meaning of words, and their synonymous and antonymous;
• examples explicit in sentences;
• the standard and colloquial uses;
• the warning of vulgar and offensive words.
We recommend the following Dictionaries (in order of preference):
Larousse Concise Dictionary: Portuguese-English / Inglês-Português by Araújo, L.; Aiken, A. Paris, Larousse.
Collins Gem Dictionary: Portuguese-English / English-Portuguese by Collins Clear-Type Press, Great Britain.