[Blueface]

While megapixels do matter if you are going large with prints, for the average 8X10, it will take quarter dissections of the photo, amplified to a new 8X10 to actually see differences if compared side by side with one another (meaning a quarter section blow up and compared to another photo taken with a camera with different megapixels).
Otherwise, to the naked eye, I agree a six megapixel is comparable to a 10.
However, if you expand to large posters or blow up the picture in a zoom fashion when editing, there will be a noticeable difference.