As for me, I simply adore ABBYY Lingvo x3. There are various versions and you can choose one that suits you best. http://www.lingvo.com/products/?id=156753

Oxford English-Russian and Russian-English Dictionaries are probably the best for not native speakers

http://www.langint.com/lexsite - is the best English-Russian Dictionary. Millions of lexical units in 300 fields of knowledge

and Google. And LOTS of online translators. And russian speaking fellaz like me ))

Besides Muller's dictionary (without any doubts the most popular in Russia), there is also Galperin's dictionary which has 3 volumes.