The monaco 9-point font is small and ugly. Can I change it to something else?
It may be ugly but it’s one of the more readable screen fonts at small sizes. If you have plenty screen space you are welcome to change it to whatever works for you. You can change the text window or plot window font under the Format menu. Very large fonts may not work well in all cases but there are no particular restrictions. If you want to change the font that will be used for new documents, first set the font and size to whatever you want and then use the “Make Default” button in the Preferences… dialog box.