I don't personally see much reason for wanting to snap to a bounding box. It's only weakly related to the underlying geometry. A (corner) node, on the other hand, is a visible geometric feature.
--bb
Snapping boundingboxes is useful for objects having a stroke, if you want the strokes touching instead of overlapping. You'll get overlapping strokes when snapping to the paths. But I don't think we need the distinction between bbox corners and bbox sides (as in nodes vs. paths), do we?
I'm trying to have as little options as possible because the snapping dialog can easily get too confusing. All the tiny detailed options are there under the hood, but I think only some subset should be provided to the user. For example, in the object snapper we currently only snap boundingbox corners to other bounding boxes, and nodes to other nodes or paths. There's no mixing of those any longer (i.e. no nodes to bboxes), which makes snapping much more intuitive. Does anyone have any objections to this behaviour?
I like the idea of only snapping to nodes at sharp corners.We will still need an option to disable snapping to nodes, as someone might want to snap to any point along a path, also to any point close to a sharp node. It would be annoying if it snaps to the node when you get close to it, so this doesn't help in reducing the snapping dialog clutter. But I think I might filter out the smooth nodes anyway, merely for improving the snapping responsiveness.
Diederik