Interesting enhancements for Microsoft Flight Simulator X:

• FSX European Ground Textures Package by Adam Mills
  Intended to solve three common complaints with European textures: the "desert" problem, winter textures and autumn textures. These modified textures reduce or eliminate the barren brown color of the default textures and improved the drab washed out fall and winter colors too.
  Part 1-8 at Simviation
  
  
• FSX Textures reworked by Aimé Leclercq
  Excellent freeware textures from Aimé Leclercq for FSX. Seasonal ground textures and road, rail and river textures. Textures cover the entire world and are more dark with a little more sharpness.
  https://sites.google.com/site/aimecreations/freeware-fsx
  
  
  
• FSX Digital Elevation Model for Alps region by Alain Ragot
  FSX Scenery--Mesh Alpes LOD11 V2. Covers French Alps and parts of Switzerland, Italy, Austria, Germany and Slovenia
  (LOD11) Mesh Alpes LOD11 V3
  
  
• FSX Digital Elevation Model for Canada by Raimondo Taburet
  FSX Scenery--Canada 19 M Terrain Mesh Part 1. The Canada 19 m terrain mesh is designed using the cded elevation models data - geobase.ca. It offers an improved terrain mesh for the whole of Canada. This is file 1 of Canada 19 m freeware project. All FSX mesh files compiled by the same author are all designed to work along each other - to provide the ultimate freeware mesh worldwide coverage for the all continents. Designed By Raimondo Taburet.
  http://www.flightsim.com/file.php?cm=SEARCH1&fname=canada19.zip
  http://www.flightsim.com/file.php?cm=SEARCH1&fname=can19x_1.zip
  
  
  
• FSL_TextureFix_V1.0.zip
  http://forums.flightsimlabs.com/index.php?/files/file/66-fsl-texturefix-v10zip/
  brilliant new FSX tweaks to improove frame performance
  (also relevant to get better result for the openVFR POI Addons)
  
  
  
• Mogwaisoft - Shade for FSX
  http://www.flightsimstore.com/product_info.php?products_id=1894
  Shade is a small program that allows you to setup custom colours/tones schemes for FSX's 3d/Terrain lighting/shadow & Fog values this allows you to alter the contrast between light and shadow tones within FSX allowing for creation of more realistic lighting conditions with much better definition/contrast.

These projects are also using Openstreetmap data in their sceneries:

• Xplane – OSM scenery (X-VFR)
  http://xvfr.beomuex.org/
• Flightgear – OSM scenery
  http://gallery.flightgear.org.uk/c1483094.html
• Microsoft FSX  – OSM scenery for Denmark
  http://www.jkelloggs.dk/scenery/denmarkmapx