hey Dutchman thanks for your comments!
here are some answers to your questions…
What particle system did you use for that?
2 regular snow emiters with about 2000 particles,… one of the emiters had a wind space warp ,… rendered as tga files, and composed in AE
About the snow you mattepainted: can you explain something of your techniques…?
it was all done in photoshop using and added layer, it was just about drawing above the picture triyng to follow the shape of the mountains and the houses in the aereal pics,… the ones of the cars are done with a lot of pictures and dozens of layers in AE
Did you use the Photoshop-blending-layer-options for instance? (like beveling?) Your snow just looks soooo good! 
not really, In some of the mattes I used real snow pictures… and a lot of cloning.
Only comment in this mini-movie
: the moving vehicles may be looking a bit tóó ‘2D’
… Maybe you could use other tricks for that for the final…?
:rolleyes: yes, you got me!
I actually did try to make those 2d images change the pespective in 3d,… I guess it needs more…:shrug:
thanks again, and hope this helps!