The (PHPTemplate-based) theme that I would like to see in core more than any other is FriendsElectric.
FriendsElectric is a good candidate indeed. Let's see what Steven has to say about this.
The only big issue with this is that FriendsElectric does not render pages with wide tables correctly. This is because of the tableless layout. There is also a problem when the left sidebar is longer than the rest. I've been unable to come up with a good solution for this, as something in the theme triggers a weird Mozilla fieldset stretching bug when I try the conventional way to fix it. Typically, overflow: auto; is used to make scrollbars appear on wide content, but this doesn't really work for big tables like we have in Drupal. Really, tableless CSS simply does not mesh with a complicated system like Drupal. Sure, it's doable for a limited site with a limited amount of options. But as a generic theme for a CMS? I have my doubts. It is trendy, and a very viable option for blogs and other simple sites, but the fact that 99% of all tableless designs can't even handle clears inside them says enough about the robustness of the whole thing. The world would be a much better place without IE: then you could actually use the table-layout model through CSS. Every other browser that matters supports it as far as I know. Finally: if FriendsElectric goes into core, who will maintain it? Putting the theme into core gives it a much higher exposure, but are any of you willing to handle the CSS that tableless layout requires? Or will it just mean more support requests to handle? Steven Wittens