For those of us who work in or near metro Washington, DC, our experience has been that we absolutely need Chicago Manual of Style and either Merriam-Webster’s Collegiate or American Heritage–or both. The first dictionary is descriptive while the second is more prescriptive.
The Copyeditor’s One-Reference-Work Challenge – Copyediting.com
If you could only buy one reference work for your editing, what would it be? Check out Erin Brenner’s answer!