I use the Hospital Drug Formulary icon on my work computer. Unlike a book, the lists add new drugs and are kept up to date.
I still have my 1998 Lipincott manual I bought when I started working, it is kept for sentimental reasons.
I have not re-upped my Skyscape for several years. I just use what's there. It's good for admin detail because it's of a nursing sort of understanding. Other than that I have Micromedex and Medscape and Epocrates (which, I almost never use).
I personally use the Davis Drug Guide for Nurses. Why? Simple... it's a school required reference. At least I can also get an online subscription for free if I get the book. I can access their drug guide on my smartphone, but we're not allowed to use the phone while on the floor so... I will also use Lexicomp, which the hospital uses. I have to wade through a lot of info when I use that, but it's a great reference! I'd use it at home if I could...