It depends what you intend to do with the images.
If you are likely to only view them on your computer
screen or print them to no bigger than A4 then it is
overkill to go much bigger than 6mp really.
But you know that marketing people are good at
hooking us into buying more than we need
If you are likely to go for bigger prints then it may
be 'really' worth going for more pixels
However, one advantage of more pixels is the increased
sensitivity at low light levels. So if you want to take
pics of your knob at night under the quilt then go for
the most you can ........... and a big zoom