While doing research for an article about machine translation, I happened to remember a piece of trivia: The biggest and most authoritative Japanese-English dictionary out there is affectionately referred to by its patrons and maintainers as the "Green Goddess", thanks to its binding and its sheer size. At some point, I keep telling myself, I plan on dropping money for an electronic version of this divine behemoth, but for the time being I'll stick with EDICT and the freeware that one can use to search it with. EDICT probably isn't anywhere nearly as complete or authoritative as GG, but it's hugely handy for the kind of quick-and-dirty lookup that you might need when translating a web page or the like.
One of the contributors to and editors of the most recent edition of the GG, Tom Gally, has a website with some wonderfully fascinating notes about the dictionary, specific entries, and books about language that have caught his passing fancy. Another great time-killer.