Washington manual is good for a little extra background reading, but I carry the Ferri manual when I am admitting patients/writing H&Ps, as I think it's better for thinking through the presenting complaints a patient has. Once I've got the patient established on the service, I'll start my reading with the Wash manul for rounds, etc.
Also good:
ePocrates or Pharmacopeia for drugs
A MUST HAVE, for me: the little Maxwell quick medical reference book; best $9 I've spent in med school - notes, labs, tons of info in a tiny book!
good luck