If you are a business student (undergrad or MBA) and for some reason you have not read this, read it and assume everyone you interview with has read it. Use its basic principles in a case study interview and you'll pass with flying colors. Anyone in business of any sort should read this book and try applying it to your own business environment. Its pretty amazing how clear your business issues will appear.
Now for the negatives. It is very out of date, so do not use any of his observations on any of the industries mentioned. His case studies towards the end of the book are so irrelevant they are not worth reading, just skimming. Read his justifications carefully, since you may find yourself disagreeing with a significant percentage.
Despite its age, this is still the primer on strategy. Read this, and then read everything else.