I'm looking into getting a new digital camera. My initial reaction was to get as many megapixels as I can afford. But then I read that for a 6x4 photo, 10 megapixels is actually overkill and more megapixels can increase the level of noise in the photo.

Is this true? If all I want to do is print 6x4 photos, will I actually get better results (less noise) from, say a 5 megapixel camera??