Recommend me a landscape filter system

[AmpedPhoto]

Hey guys and gals I am looking for a good but affordable filter system for my landscape photography. I don’t spend much time doing landscapes but I want to do a little more work.

My goals are to really get true sky colors without using PS and getting it right in camera. So please post a link of a recommendation!

Thanks Mike

[jeppoy]

P Cokin Filter holder+Singh-Ray ND filters or other brand because Singh-Ray is $90 a glass. I think P Cokin makes ND filters as well. The holder by the way is stackable.

http://www.bhphotovideo.com/c/search?Ntt=P+COKIN&N=0&InitialSearch=yes