OLIVER PABST SCENERY
His scenery is known as one of the best freeware available - unfortunately so far only for Mallorca and Bremen.
Screenshots and more details will follow. Take a look at: http://www.flightsimmers.net/airbase/opabst

AEROSOFT SCENERY
Another top-quality scenery producer. Only one mistake - not for free :-(
But if you are interested espeacilly in the best Scenery available for German Aiports, your money is well invested into the German Airports Series. More to be found here later. Taje a look at: http://www.aerosoft.de