Chambers-Murray is the 3rd edition of Smith’s smaller Latin-English dictionary. It was entirely re-written by Lockwood in 1933 and considerably abridged. I compared a few entries from my 2nd edition (1929 printing) with the Chambers Murray (3rd ed.). Many definitions are shortened in the newer edition, examples are removed, extra meanings are cut out. Many words are altogether removed from the newer edition. Proper names in the 2nd edition were set apart in the back of the dictionary, which as Smith explains in the preface makes it easier to find common words. Unfortunately, the 3rd edition inserts them into the main text.
The Elementary Lewis (or Little Lewis as it is often called) is the best choice still in print. Smith’s 2nd edition is slightly broader in scope, but Lewis gives more examples. If you’re limiting your reading to the major authors mentioned in the Preface (Terence, Caesar, Sallust, Cicero, Livy, Nepos, Vergil, Horace, Ovid, Juvenal, Phadrus, Curtius, Catullus, Tibullus, Propertius, and Tacitus in his larger works), you will need no other dictionary, as it contains all the words used by these authors.
Of course, the price difference between Lewis and Chambers-Murray is pretty steep. This may be due to the fact that the Lewis is a hardback with an excellent binding, whereas the Chambers-Murray is a glued paperpack. However, the Lewis is a facsimile and not printed from original plates, therefore the text is not very clear, but still very readable.
I wouldn’t bother at all with the huge Lewis and Short or the OLD for casual reading. They are good for researching particular segments of text, but the bulkiness and the number of entries makes them impractical for reading large quantities of text.
One final remark. All the dictionaries on the market, except the unabridged Lewis and Short, are meant for classical Latin. It is unfortunate that there exists no smaller dictionary with a wider scope for students who are also interested in Patristic, Medieval, and Renaissance Latin.