Ctrl+u turns snapping on/off. I use it alot when switching between wanting to snap to a node and wanting to draw freehand when close to a node or other path/object.
Ctrl+h is another very handy tool - toggles the selection highlight on/off. Select some text and hit ctrl+h you'll see what I mean. When you've got effects applied, the highlight makes it hard to see the actual object/text, so use this to reveal it.