Some of the apps that are coming out for mixing boards and DJ scratching — they all look really cool, but they suck to use. You can’t physically turn a knob on the iPad screen — so why make knobs an essential part of your interface?
Finally, give users what they want — and a little more. In addition to enabling users to use your service effectively and efficiently, make them also think, “Wow, this application is genius.” Exceed their expectations desirably. If you do so, they will use your website or app not because they have to but because they want to.