plug: Try App Sketcher (http://www.appsketcher.com) if you need to show interactions in your prototype. App Sketcher creates prototypes in HTML/CSS/JS (no coding needed) that can run in any browser.
I am with you:) I hope App Sketcher can bring in some fresh air. It's not using images or graphic objects to emulate web - it uses real HTML elements and jQuery UI components as building block on top of a webkit based design surface. So in a sense it gets you covered from concept/wireframe to prototypes and even into early phase of development.
plug: Try App Sketcher (http://www.appsketcher.com) if you need to show interactions in your prototype. App Sketcher creates prototypes in HTML/CSS/JS (no coding needed) that can run in any browser.