I remember Oxford Handbook of Clinical Medicine (OHCM) since its first edition and it looks it has only gotten better. When preparing for USMLE several years ago, I used to refer to OHCM and First Aid for USMLE often and it helped - my scores were 96, 97, 93 on USMLE 1, 2 and 3 (99 is the maximum). The study plan was based on those handbooks, "regular" textbooks, self-made notes, mnemonics and mind maps. It was surprising how long the effect lasted -- my in-service exams scores during the internal medicine residency were 98, 96, 98 during PGY 1, 2 and 3 respectively, and I did not need to study more than 2 weeks to pass ABIM.
Scores are nothing without sound clinical judgment, of course. OHCM was the handbook that I found most useful and reader-friendly. It goes beyond being simply a medical handbook, for a start, it often reminds you that patients are much more than "strokes" or "pneumonias" and there is more to life than medicine. The section Thinking About Medicine -- Your Inner Peace on ClinicalCases.org is named after the first chapter of OHCM -- you can browse through the book on Google Books or download the chapter for free from Oxford University Press here:
Chapter 1: Thinking about Medicine (PDF, 464 KB)
It is nice to see that OHCM now even has an iPhone edition ($44.95).
Mini Oxford handbook of clinical medicine By Murray Longmore, Ian Wilkinson, Supraj R. Rajagopalan from Google Books:
Skyscape books for iPhone. Skyscape.com, 08/2007.
How to Score Well on the Boards? Clinical Notes, 2004.
How to Study, Clinical Cases and Images - Blog, 2007.
Nine facts you may not know about the Oxford Handbook of Clinical Medicine (OHCM) http://buff.ly/1crUrgA
Image source: UnboundMedicine.com.