I would like to hear your opinion to the following screenshot: http://www.jray.de/scrdump010.jpg Thanks!

This should go in the visual arts forum.

I like how it looks, but the building roofs look a little funny. Apart from that it looks nice.

The bridge shadows need some heavy work. Lighten the contrast on the road bevels, and as boolean said, fix those roofs (starting by getting rid of the outlines and borders).

For most shadows, instead of just using a cheap "drop shadow" (it's too soft while being too dark), try and use two fragmented lighter shadows. For reference, check shadows on the walls in your room.

The water is looking pretty good.

I'd also seriously revamp your scroller compass.