I love the skyline, really good idea! Not a huge fan of the background you have there. Someone suggested doing a gradient background which could be really cool. It's pretty easy to do I have seen people do it on surfboards before their final clear coat.
This is my friends longboard, he has kind of the same idea but did out skyline (Calgary) with black and clear griptape instead of doing the bottom.
I have no artistic talent so I just sanded the original graphic off mine, and stained unevenly it to look like an old school water ski. Then i put a matte protective coat on it instead of a shiny one so it totally looks vintage. This summer though I think I'm going to give it a flat tail and a pointier nose and router like surfboard shaped rails all around it, plus some red stripes on the top.