When asking customers what they want, the trick is to ask the right questions.
Henry Ford was quoted as saying, "If I had asked customers what they wanted they'd have said, 'A faster horse.'" I'm sure that's the case. I'm also sure that if Apple had asked customers the same, no one would have said, "A wallet-size device to carry around my music."
For that reason, the right question only sometimes is, "What do you want?" More often, the question should be along the lines of "What problem do you need to solve?" or "What unmet need do you have?" Keep in mind, though, that the question is often not that direct. Perhaps, for example, by conducting surveys to determine issues people were having when traveling on horseback, Ford might have confirmed several reasons customers would want a car: travel on horseback took too long (people wanted to get to their destinations faster); traveling in the elements was uncomfortable (they wanted to stay dry when traveling in the rain); they didn't want to have to take a wagon if they we're just going to market for one or two items (they wanted to carry more than a satchel but not so much as a wagonload).
Here's another example: During presentations about understanding customer needs, Peppers & Rogers Group Founding Partner Martha Rogers, Ph.D., often says that if an airline was to ask what she wants, she'd know immediately: She'd be willing to pay a fee to reserve the overhead bin above her seat. If you ask most other travelers what they want from an airline, few would think to say, "A guarantee of overhead bin space." But if you asked them what might make their trip less stressful, "guaranteed overhead bin space" would likely be among the top five items.
Ultimately, it comes down to asking a mix of questions, direct and indirect, to understand customer behavior, concerns, preferences, and needs. This deeper understanding, along with the insight of the product experts on your staff, is what will lead to the big innovations.