I'm just running this by the mailing list to see if it's worth a feature  proposal before submitting it.

Feature: boolean modes for all drawing tools.  1. Select an existing object 2. Select a tool of your choice (say... Pencil), with Exclude mode activated for example. (boolean modes appear as small icons in  the toolbar) 3. When you draw a shape, the originally selected object does not get un-selected. When you finish drawing your shape, Inkscape automatically chips away at the original shape. The original shape still does not get un-selected until you select something else, so you can continue chipping away at it.

Exclude is just one mode, you can have addition, intersection, etc. It applies to both drawing tools and shape tools.

I was inspired for this by 2 things: - Krita's "erase" mode. You can basically take any paint tool and  activate an erase mode to make the eraser much more interesting. - I never use the eraser. The round shape just isn't too convenient. : ( Thinking about it now, Gimp has similar options for selection tools.

I often draw a rough shape and slowly refine it by zooming in before adding to it or chipping away at it, so this feature would streamline the workflow a lot. (also, it took me a while to remember the boolean operations, I imagine shortcut-phobic users would appreciate this feature a lot)

Also makes it easy to make quick holes.