ONLINE DICTIONARIES. WHICH ONE SHOULD I USE?

Hi, everybody!
you know, there are thousands of online dictionaries... so, wich one should I use???? That's a question many students ask me. Well, it depends on what you're looking for. If it's a simple translation, even the google translator is good. But if you want more advanced information about the word, or if it's an idiom, or a phrasal verb, then you're gonna need something more specific. Here are some useful links:
http://dictionary.cambridge.org/dictionary/american-english/ - for American English
http://dictionary.cambridge.org/dictionary/learner-english/ - if you want more information and examples on how to use the words
http://www.macmillandictionary.com/ - a very complete dictionay

So, try these ones and say what you think about them!

Carmen