Another great post fron Des Traynor. This one about where specifically you should use recall (e.g. a blank interface where the user needs to know what they're looking for) versus recognition (e.g. a list of categories to entice the user to click in).
Some key points:
Recall needs an exhaustive data set before it works well.
After a couple of zero result searches you’ll inevitably lose your customer, when they would have been happy to browse and purchase from your kitchen category.
Your search results page is a marketing page. You should spend time ensuring that it presents products well, and provides key information to inform a customers (e.g. price, delivery date, availability etc). Displaying results in the well known Google style works, but is missing a good opportunity to present your products as well as possible.