Anyone old enough to remember the days when executives had secretaries should be able to confirm that the well-thumbed dictionary most likely to be found in the sec's office was the Concise Oxford. It was also the dictionary that a wise parent might give to their child going off to college or university. It earned this position by combining the authority that came ultimately from the OED with the common sense and practicality that chose the right subset of words to represent the English used or likely to be encountered, in real life by real people. To those who know about popular dictionaries in the USA, I can just say "this is our Websters Collegiate".
You can of course get one-volume dictionaries with many more words - the full versions of Chambers and Collins, and the Oxford Dictionary of English. Very good dictionaries all, but a notch heavier and more expensive. But for clear coverage of the vast majority of words you're ever likely to meet, the Concise does the job. It does more than the job in some cases, with usage and history notes for various words. The usage notes are the more useful (and more frequent), telling you about things like the times when round is used instead of around, and vice versa, or the offensiveness of 'spastic' in modern use. As another reviewer points out, pronunciations are only given where they're not obvious to English speakers. Not a problem, I think, unless you're a non-native speaker of English - but there are dictionaries designed specifically for use by students of English, which I suspect deal with this issue.
Placed right in the middle of the dictionary is a 24-page "Centre Section" with information about the way lexicographers deal with English words, lists of ineteresting words of various kinds, and a guide to good English. This placement seems a bit odd, but the shading on page edges makes it easy to find (for other pages, this does a pale grey letter-less imitation of thumb-indexing - helpful once you remember a few things like "the fat letter near the end is S"). My guess is that some work with real dictionary users discovered that having this stuff at the beginning or end was a good way to ensure that almost no-one found it.
A brief mention for the reason I own too many dictionaries - the Concise Oxford is one of the two dictionaries used as a standard reference by the Times crossword (the other is Collins). Lots of people will tell you that "Chambers is the only dictionary for crosswords". If you're doing the fiendish barred-grid puzzles like Azed and the Listener this is true, but except for the odd bit of wildness from Araucaria and the like, the vast majority of answers in a daily paper cryptic crossword (proper nouns excepted of course) will be found in the humble COED.