Megapixels aren't important?

I suppose megapixels are not important if you know exactly what you are taking and how you are taking it. Sometimes however, the megapixels really help.

In this one shot of a waterfall, I took a wide landscape shot. I knew part of the picture would be washed out as the morning warmed up and the sun started its climb to its apex point. It was only 9am but the sky was quite brighter than the shadows of the fall. I took the picture anyway.

Here, I cropped the picture, removing the washed out part and got this shot of the waterfall. Still lots of pixels in the cropped version. Not too bad.