For that map, I'd say Inkscape would be the tool of choice. Inkscape is to Illustrator as Gimp is to Photoshop. I wouldn't try something like that drawing with a mouse, though. I'm not sure what Inkscape's terminology is, but when I created this map, I used Illustrator's Pencil tool to draw the coastlines and contours. Draw the lowest, largest shapes first, and move upward. The beauty of working in Illustrator is that you don't actually have to style it until the end, since you can change fills and strokes at any time. I'm fairly sure that Inkscape works similarly.