Benefit of asp.net control

Use asp.net controls for better state management and event handling mechanisms. If your site do not have requirements to save the state for page post backs, then use HTML controls. Basically what is your web application purpose?

The other posts are correct. Asp.net controls will render to html controls in the grand scheme of things, the difference is that they were created to postback to the server. Anytime you need to perform server side computing you should use asp.net controls and keep in mind that html controls could also be use server side if you add runat="server".

Am still using most of the HTML controls for web site developments. Its upon you which one to use. The only difference is, you can even use HTML controls without runat="server". If you want to use HTML controls in server side, then runat="server" is must. We can asp.net controls is extended version, with properties, methods that HTML controls easily dont' have. Finally, all the controls get rendered into HTML controls only. So no need to worry, try both of them so you can learn the things.