This is a soft autumny color scheme.

You can obtain the look in the screenshot by using the following:

Plasma theme: Glassified 3.1.0 (http://www.kde-look.org/content/show.php/Glassified?content=81388)
Wallpaper: ubuntu-smooth-chocolate (http://my.opera.com/jsemgel/albums/showpic.dml?album=297191&picture=4388446)
Plasmoids: Folder View, Dictionary, Google Translator, Calculator, Calendar
Left panel (autohide): Konsole, KCalc, KWrite, Konqueror, KMail, Akregator
Bottom panel: Application Launcher, Quick Access, Device Notifier, Trashcan, Pager, Calculator, Dictionary, Task Manager, Show Desktop, System Tray, Digital Clock
Widget style: QtCurve (Gleam.qtcurve) (http://www.kde-look.org/content/show.php/QtCurve+(KDE4,+KDE3,+&+Gtk2+Theme)?content=40492, http://kde-look.org/content/show.php/Gleam+(qtcurve+config)?content=114867)
Window decoration: Nitrogen (http://www.kde-look.org/content/show.php/Nitrogen?content=99551)
Color scheme: glad-Autumn2 (this one, available in the download)
Icon theme: Lila Red (http://kde-look.org/content/show.php/Lila+icon+set?content=23499) converted to KDE4 icon theme using a conversion script
Fonts:
General: Fontin Regular 9
Fixed width: Luxi Mono Regular 9
Small: Fontin Regular 8
Toolbar: Gentium Regular 9
Menu: Fertigo Regular 9
Window title: Hasenchartbreaker Regular 11
Taskbar: Fertigo Regular 9
Desktop: Fontin Regular 10
Cursor theme: Oxygen (standard KDE cursor theme)