I haven't seen one better than the Oxford dictionary published by Oxford University Press. But be warned: there's a book called "Oxford Hebrew-English Dictionary" that's published by Kernermann Publishing that is NOT the same thing. I'm not sure how it compares to the "authentic" Oxford except that it's less expensive.
If the option is available to you, try your local library. Our local library is pretty good and has the Pimsleur audio course for Hebrew and a few different types of Hebrew dictionaries. Check your local bookstore too and peruse their selection.