These books are required reading for any website owner. These books have all helped me in some way in my ecommerce ventures, and I highly recommend them to anyone that is in or is interested in successfully creating and running websites.

I recommend finding used ones at amazon or barnes and noble, which are normally much cheaper than buying them new.

Website Usability
Seth Godin – The Big Red Fez
Steve Krug – Dont Make Me Think
37Signals – Defensive Design for the Web
Homepage Usability
Designing Web Usability
Prioritizing Web Usability

Website Design
Dan Cederholm – Bulletproof Web Design

Marketing
The Eisenbergs – Waiting for Your Cat to Bark
The Eisenbergs – Call to Action
The Eisenbergs – Persuasive Online Copywriting

Print and Business Design
Before and After – Graphics for Business
Before and After – Page Design