Just to mention, for me the accepted answer does not bring the desired result with Mathematica 10. Instead, what I get when running
Plot3D[
Cos[2 Norm[{x, y}]], {x, 0, 10}, {y, 0, 10},
Lighting -> {"Ambient", White},
PlotRange -> All, Mesh -> {20}, BoxRatios -> {1, 1, 0.1},
Boxed -> False, Axes -> False]
is this:

However, a color function did the difference for me:
Plot3D[
Cos[2 Norm[{x, y}]], {x, 0, 10}, {y, 0, 10},
Lighting -> {"Ambient", White},
ColorFunction -> Function[{x, y, z}, White],
PlotRange -> All, Mesh -> {20}, BoxRatios -> {1, 1, 0.1},
Boxed -> False, Axes -> False]

Lighting -> {White}is enough. – xzczd Apr 03 '13 at 04:54PlotStyle->Whiteis necessary to deal with an orange plot. One can also addPlotPoints->22, MaxRecursion->0to obtain really old-school plot :) – ybeltukov Sep 07 '14 at 13:11