Remember, the web isn't about control. If a visitor to your site is familiar with using a browser's native form doodad, you won't be doing them any favors if you override the browser functionality with your own widget, even if you think your widget looks better.

If there's one thing you learn by working on a lot of different Web sites, it's that almost any design idea--no matter how appallingly bad--can be made usable in the right circumstances, with enough effort.

Most sites need to prevent breadth — many many pages that are organized cohesively. A site that presents a single webpage is unlikely to present sufficient depth of content to justify extensive SEO.