Thanks! I'm glad you like it, I wasn't sure whether it would come out OK when I aimlessly started out...
You're definitely right about the grass texture. I've updated the map to take on your comments - hopefully you'll be able to see a less 'zoomed' texture (and therefore less pixely). I've attached two new versions, one with the poster edges filter run on all except the grass and the other without the poster edges filter run at all.
Personally I like the poster edges filter, I think it gives the map a more hand drawn feel rather than the crispness of a photoshop creation. Don't know how you feel about it.
With regards to drawing the buildings, it wasn't that painstaking - I simply drew a building pattern, dropped it onto the map and masked out the buildings I didn't want. Much quicker and that's why it's slightly repetitious...
The trees are hand drawn with a stipple brush and the water makes use of the glass / ocean filter.