Free open-source ToDo-List / Time Tracker Super Productivity is out in version 6. Among lots of other improvements and minor fixes, it brings support for WebDAV sync and custom background images.
Check it out and let me know what you think!
Special thanks go to the gifted Hannes Pasqualini from Papernoise, who helped me - among many other things - a lot with the very sexy new redesign, and Manuel Will who allowed me to use one of his fantastic images as the default background image. Thank you!!!