Smart PolyChart is a simple CommandData plugin which draws a neat bar chart from the polygon counts of all polygon objects in a scene.
You can download it here – the source is documented.
The part for users:
Just drag it into your /Plugins folder and open it from the ‘Plugins’ menu. The ‘Update’ button refreshes the view, a click on a column will select the corresponding object so you can optimize or remove it to lower the scenes polygon count.