Originally Posted by Nightyume
Translation dictionaries do tend to be more limited.
And you're wrong, the most comprehensive Merriam-Webster is the Unabridged
(it's a happy tongue out, not a mocking raspberry, and I'm only clarifying as I'm new and don't want to make a bad first impression)
I have both the collegiate and the unabridged on my cell (and the collegiate on my bookshelf). In my experience, anything less comprehensive than the Collegiate (be it Webster or Oxford or whatnot) is of little value to me personally as the words that tend to stump me aren't in them.
My brother-in-law is a word freak and loves that his reference library at work carries the Oxford English Dictionary in it's 20 volume glory plus 3 additions volumes. There are words in there that haven't been in common use since Shakespeare was scribbling. The CDROM version of the OED along with the Historical Thesaurus is available via the corporate network for online lookups while at work or using the VPN. A great resource for those authors in love with polysyllabic logorrhea and for those who try to read and enjoy their work.
Personally, I settle for the Canadian Oxford English Dictionary which has a very good grip on the way that Canadian spelling wavers between the UK and the US usages.