Here are some of the outliner settings I'm using with Circus Ponies Notebook:
Add New Cell with Return key:
Preferences -> Keyboard -> Pressing Return while editing a cell's text: -> Ends editing and adds a new cell (List Mode)
Outline -> Cell Spacing -> Double-Spaced at This Level
Outline -> Action Items -> Add a Checkbox to New Cells
Hide Completed Items:
Outline -> Action Items -> Hide Completed Items
What I'd like to see when in List Mode:
1.) Checkboxes as default for new list items.
2.) 'Show Checked Items' and 'Hide Checked Items' option (right now there's a 'Hide Completed Items' which, while functionally equivalent to 'Hide Checked Items', for some reason doesn't ring right to my ears. I prefer the more direct and graphically relevant (i.e. we're talking checkboxes), 'Hide Checked Items'.
3.) Columns. I miss having a time-stamped 'Start' column and corresponding 'End' column pair on a list item (great option to have for project tracking, for example).