Alex Kirs has created a Toggl Dashboard widget for Mac. Check out his site: http://home.kirs.name/toggl-widget
There is also a longer article on the widget in popular Russian technology blog – http://habrahabr.ru/blogs/arbeit/73158/

Here’s a quick overview of your browser and OS preferences (during the last 7 days). It was a surprise that Chrome has become more popular than IE.