There are a few English-Greek dictionaries that have been in Community Pricing for a while and I'd love to see them come through.
One is Berry's 1158 page work at $12 http://www.logos.com/product/15774/the-classic-greek-dictionary-in-two-parts-greek-english-and-english-greek ,
another is Yonge's 536 page work at $6 http://www.logos.com/product/15746/an-english-greek-dictionary and
another is Fradersdoff's 649 page version at $8 http://www.logos.com/product/15750/a-copious-phraseological-english-greek-lexicon.
Q: Why on earth would you want an English-Greek dictionary?
A: To consider alternative words available to the author that he overlooked in choosing the words he did.
For example consider the Greek word epi (a notoriously difficult word to translate). When wondering whether it might be translated 'before' (an unusual but possible translation), it is helpful to consider what other prepositions could have used instead. A quick consultation of an English-Greek dictionary might suggest pro. So could pro have been used instead? Indeed, if we noted that pro had already been used in the surrounding context of the passage, then the change of preposition in this context from pro to epi would suggest that the author is using a specific meaning of epi not covered by pro and therefore suggest it shouldn't be translated before. In short, the use of a basic English-Greek dictionary helps our critical analysis of the text, not always, not even often, but at times it could be very helpful.
Guys, these dictionaries are all cheap. Have a look at them and take your pick. Indeed, now that I've started this thread on dictionaries, it might be useful for more knowledgeable people in Greek to comment on which dictionaries they think are the best out of these 3 to help guide me and others 
Thanks
Paul