Here's a list of some of the great resources that have been used for the material on MedicalPhysiology.co.uk. There are also a few other really useful books and links that will hopefully be of interest.
Textbook of Medical Physiology - Guyton & Hall
'...one of the must have books for any medical student or clinician.' Read the review
Principles of Physiology for the Anaesthetist - Power & Kam
Biochemistry - Berg, Tymoczko & Stryer
Essential Haematology - Hoffbrand & Moss
Respiratory Physiology: The Essentials - West
The Doctor's Guide to Critical Appraisal - Gosall & Gosall
'...an easily accessible introduction to the vast topic of critical appraisal.' Read the review
Run by the author of this site Rapid Sequence is an on-line journal club and blog for all things anaesthesia and critical care related. Check it out here.