I'm embarrassed to admit, I haven't bought a new drug book since I graduated :imbar (thank goodness my hospital buys new ones each year). My favorite, though, is the Davis Drug Guide for Nurses.....it lists all drugs by name in alphabetical order, rather than by purpose, which is why the other drug guides tend to confuse me. I mean, if I knew what a drug was for, I wouldn't have to look it up, unless of course I had a question about interactions or dosages. The Nursing series is good too, even though it does have that little quirk of listing drugs by category; the information is clear and concise, and it's very readable.
The one I do NOT like is the PDR---the print is so tiny that I have trouble reading it even with glasses, and there's a lot of doctor gobbledegook; it's unnecessarily complicated and heavy to boot.
Just my two pennies' worth.