I'll confess to being a fan of Seth Godin. He has a great blog which is worth subscribing to, as it's normally nice short soundbites of really useful information.
Here's his most recent example:
There are two kinds of purchases: Either you are replenishing (you know precisely what you're about to get) or you are exploring.
Books and movies are almost always purchased before they are consumed. A bottle of Coke, or a return visit to a massage therapist, on the other hand, are replenishments of a known quantity. You might buy something for the satisfaction of owning it, or of owning one more, but that's different than buying out to find out what it does.
Neither is better or worse, but they are very much not the same.
If you sell an exploration, your customer is taking a chance..."
Try before you buy (or buy, then try) - Seth Godin
Food for thought, and by getting in to the mindset of your customers you should have a better idea of how to market your products or services.