About Dictionaries
Click Dictionaries Online on the right sidebar for free online dictionaries. They are good enough for general use.
For Pronouncing Dictionaries, I prefer Cambridge English Pronouncing Dictionary to Longman Pronunciation Dictionary, because Cambridge, in general, provides detailed notes on the uses of weak and strong forms. It also allows users to perform cut-and-paste, which Longman does not.
For professional use, I recommend the Oxford English Dictionary (OED), a multi-volume dictionary, as shown in the picture. The OED is revered as the definitive dictionary for the English Language. When I was an English student more than 10 years ago, I purchased its CD-ROM version, which cost me CAD$600 or HK$4,800! Now it's even pricier, charging US$295 for an annual subscription! For the story behind the composition of OED, you can read Simon Winchester's The Professor and the Madman: a Tale of Murder, Insanity, and the Making of The Oxford English Dictionary; Hong Kong Central Libraries possess several copies.
Or, you can use the compact OED, a single volume version. I used to also have the compact version; it came with a magnifier! English Literature students should use the OED, not the general dictionaries. Once you use the OED, you’ll find you don't really want to use any others.