Create Ubuntu Artwork for as many applications in universe as possible

I think that many applications lose the feel of Ubuntu when you open them up - having seen their nice lookin icon in the Applications menu - and the icons are different to what you see everywhere else. In Windows, shell32.dll contains a standard set of icons, and ~all programs use them. There is no equivalent in Ubuntu, so applications have local icon sets, and local themes. Firefox, for instance, has an Ubuntu theme, but it's not included by default - even though it is the default web browser. Evolution has Ubuntu artwork, but many people use Thunderbird instead, which doesn't have a theme. This is why I think that Ubuntu needs Ubuntuification.