For the average consumer...more MP means better.  The manufacturers also know this...so they are taking advantage of this marketing opportunity...can't blame them....

That being said, advancements in noise attentuation are being made with each generation of sensor design.

I think Danny has really hit on a critical component, that being optic quality.  It appears that currently we have reached the optical limit to resolve all those megapixels...so...much more (expensive) work will need to be done in this area.

BTW...I wonder how many camera buyers are aware that many camera lenses are made of plastic?

In youth, we learn....with age, we understand.