Everest Dictionary is a great free dictionary. This version contains 37 dictionaries in nine languages (English, French, Italian, German, Spanish, Portuguese, Hungarian, Romanian, Bulgarian). Besides the dictionaries, Everest also has a Text Translator, an Instant Translator, a Pronunciation Agent, and a Game to help you learn a foreign language!
There are many different search options and search history. Features a speech agent for the English words and a multi-language Interface.