They visited and left, bored, without a unique impression of the brand, their credit cards nestled away in their designer leather wallets. You should have given them a sense that the site knew just a little bit more than they did, and that their browsing would be rewarded with a unique product that not just any other person could find. You made it too easy, and you insulted their sense of style. The key is to understand your users much like an anthropologist understands his cultures. Don't just reduce users to lab mice who respond to heuristic stimuli over and over.
Users are smarter than that, and they can sense a pedantic experience from a mile away.
Step out and observe. Get to know what turns them on, what turns them off, what they buy, and what you can assume they already have. Only then can you begin to discover what triggers both positive and negative emotional responses, and how much your users can be challenged. Don't throw away those heuristic lists just yet. Use those standards as a metric to measure how far you can stray from interface conventions based on what you learn about the users.