I own hard copies of all 4 major latin dictionaries:
2. Chambers-Murray(a re-sale of Smith smaller latin dictionary).
3. Lewis - Elementary latin dictionary
4. Bantham's new college.
All the first 3 dictionaries suffer from the fact that they are written under old lexical methodologies and in archaic(British) English. They are all about the same scope. Cassell's, if you read the preface, has been revised too many times, and from personal experience it sometimes gives false quantities for certain words. Chambers-Murry(0550190031), and don't let its old name full you, is the most detailed and includes later authors, such as Ausonius. It is about the same size and price of Cassell's but it is only latin-english.(16$~)
The elementary is fine, archaic, detailed enough but is twice the price. Its highlight is the etymological appendix at its end, which is not even included in the full lewis and short.
The Bantham is an excellent quick reference, and its interface is excellent, only suppressed by the OLD.
Though I am against the use of big dictionaries, and dictionaries in general after about two years of working knowledge of a language, as they slow your progress down, I think the oxford Latin dictionary(0198642245) is a choice far better than the lewis and short, if you decide to go the pricey and bulky way.
Both Lewis and Lewis and Short are available online, in case you bump into philological issue, which you can't find a solution to it otherwise: