I am a new member here, and am happy to have found this site.
Any Spanish/English, English/Spanish dictionary you recommend?
This site's administrators are working to improve this site's dictionary. I congratulate them on this noble project.
Another bilingual dictionary worthy of mention is Reverso Dictionary. No bilingual dictionary is perfect, but this is a good one. It has translations between English and seven languages (one of which is Spanish, of course). There is also an English-only dictionary, and several specialized dictionaries. This is my first choice for an English-Spanish/Spanish-English dictionary.
Of course, the "official, authoritative" Spanish dictionary is the one qfreed already mentioned ... el Diccionario de la Real Academia Española. It is very particular about spelling, including tildes, and does not accept capital letters on common (non-proper) nouns.
See this page at elcastellano.org for a list of countless varied Spanish dictionaries.
Also, languagerealm.com will give you links to a number of specialized dictionaries in Spanish/Spanish-English, and other languages as well.
They would probably excommunicate me if I didn't mention that this site has its own dictionary. Click on the tab that says diccionario or dictionary depending on your page language.
This is a link to another important resource: http://www.rae.es/rae.html (online Spanish only dictionary)
If you Google spanish/english dictionaries you'll find many. Which is best is probably a personal preference, but since I'm a member here I suppose I'd better say that our is the best (but then again Heidita's off site at present so maybe I wouldn't have to spend the entire day in the corner if I recommended a different one. )
¡Bienvendio/a al foro!
Welcome to the forum. Well there must be dozens out there but for a start, why don't you try ours?