Maybe these suggestions are aimed at UK junior doctors more than our US colleagues, but the Oxford handbooks are really good:
Oxford Handbook of Clinical Medicine (for medicine and surgery) - J. M. Longmore, R.A. Hope, Murray Longmore, Ian Wilkinson, Estee Torok - ISBN: 0192629883;
Oxford Handbook of Clinical Specialties (for O&G, paeds, ENT, primary care, etc) - Judith Collier, Murray Longmore, Peter Scally - ISBN: 0198525184;
Oxford Handbook of Acute Medicine (for on-call in medicine, probably more suitable for 2nd year residents (SHOs in UK) - Punit S. Ramrakha, Kevin P.K. Moore - ISBN: 0192626825;
There are also more specialist handbooks for surgery, general practice, haematology, ...
The Oxford Handbook of Clinical Medicine is a bright yellow and green pocket-sized book. It's called the "cheese and onion" or "the yellow book" amongst students and house officers in the UK. EVERYONE has one! It covers everything, from clinical method to normal values, from management of medical emergencies to management of the difficult feelings that being a first-year doc on the wards can engender in us.
I would recommend taking a look at these books. I'm sure their content will cross the Atlantic very well, save the spelling of words like paediatrics and haematemesis!
Adrian.