Realistic floor created with Blender 2.66 and Cycles
Why is the file so large for a plane?
Because of the high resolution textures.
great job. how do you apply the normal maps?
I used the Node Editor
Looks exactly like an intermediate result of one of BlenderGuru tutorials "The Secrets Of Realistic Texturing" - http://www.blenderguru.com/videos/the-secrets-of-realistic-texturing/ :)
Excellent , thanks