Time for me bite the bullet and actually post something, I suppose - I've been lurking (and hopefully absorbing ideas and advice) for far too long.
Welcome to Kerandia, a flooded world for a D&D (4e) campaign.
The basic pretext for this world is that war between Teiflings and Dragonborn came to an end 1232 years ago when each of the sides were tricked into performing a ritual which would drown their enemy's armies. The rituals were actually being coordinated by a Bad Entity and had the effect of opening a gate to an elemental realm of water, flooding most of the world and displacing survivors into scattered communities (to achieve the "points of light" effect together with explaining the high racial mix in survivor communities).
I wanted some relatively large landmasses for the lower levels of the campaign before my brave heroes buckle their swashes and take to the high seas for mid-level adventures. They'll start moving on to exploring a network of teleportation circles towards the end of the campaign, the successful conclusion of which may well see them restoring the world to its pre-flood configuration.
I played with settings in Fractal Terrains for a while until I created a world which featured a pleasing arrangements of islands and then traced this map in Campaign Cartographer 3. I've adapted the overland b/w style (quite a lot for some layers) and am deliberately keeping colour use to a minimum.
I know I've made the settlement icons too small (yes, there are 8 settlements on the map, honest!) but that's easily remedied. The bigger issue is what to do about the hills. At the moment, they're denoted by a brownish contour line - I didn't want to use icons for the hills on the campaign-level map, reserving icon use to show the mountains at this scale. Any suggestions for improving how these areas appear would be very much appreciated.