Sunny

UPDATE: ingolemo has updated v0.3 of his theme, incorporating these improvements :-) -- http://gnome-look.org/content/show.php/Ubuntu+Sun?content=116344. Please use his metacity theme, which is under active development.

This metacity theme uses the colors of -- and therefore will fit well with -- virtually all Gnome/GTK2 themes.

The attached screenshots show Ubuntu 9.10´s Human theme, but with Sunny as the window border theme and various colors for selected items (instead of brown). To replicate the same exact look, just do the following:
1. Click on System -> Preferences -> Appearance, and choose Ubuntu 9.10´s Human as your theme (install it if you don´t already have it).
2. Click on Customize -> Window Border, and choose Sunny as your window border theme.
3. Click on Colors and change the Selected Items Background to any other color of your choosing, and close.

This theme is an update to the metacity component of ingolemo/plippo´s Ubuntu Sun theme v0.2 (http://gnome-look.org/content/show.php/Ubuntu+Sun?content=116344).

Specific improvements to ingolemo´s v0.2 theme include: (1) fixed all edges and corner highlights; (2) replaced the up-down window-button animations with subtle button highlights on hover and click; and (3) added visible buttons to all unfocused windows.

2009.12.05 - updated info
2009.12.04 - added instructions for producing exact same results shown on screenshots; listed concrete improvements to ingolemo/plippo´s theme; updated license info.
2009.12.03 - fixed as best as I could a minor (almost unnoticeable) bug with the edges of windows.