Preview: 

Marinelli is a 3 column, tableless layout theme with a wide image banner and a "top-tabbed" primary-links system.
Here you can try a live demo

Sorry but 5x version is no longer supported
Features
Flexible 3 column system
Optional dropdown menu per Primary Links Just activate it in the theme settings page
rotating banners
css classes for core modules and better font managment: all sizes now are in em
better headings management for SEO
4 seperate stylesheets (layout.css, graphics.css, typography.css, links.css) to speed up theme customization and maintenance
Css image preload with jQuery
3 Subthemes included
Gnifetti with both sidebars on the left
Giordani with content in the middle
Alagna marinelli with different typography and graphics

valid XHTML 1.0 strict and CSS2, Accessibility: AAA (http://www.totalvalidator.com/) looks great in FF2,FF3, IE7, IE6, Chrome, Camino, Safari and Opera.