If you have the same sensor on an 8mp and 12mp doesn't mean the 12mp is going to take better pics I guess is my only argument. I just think there's too much emphasis from sales people on megapixel, nowadays every new camera is fine megapixel-wise for me.
You're absolutely right, a 12 isn't necessarily going to take better shots than an 8 if the camera is shit. However, there are some fantastic higher MP cameras out there and I would still go for a fairly high MP count. It's ultimately more versatile.
There is also a software for converting Tiff images to giant billboard sized images that aren't all grainy. I went on a workshop with some "pro" photographers and he had one image blown up to 7' wide by 5' tall from a 12mp camera and it wasn't all grainy unless you put your face right up 2" from it.
Yeah. Even Photoshop will do a pretty good job enlarging images. There used to be a software package years ago called Genuine Fractals that was used to enlarge images for things like billboards. Looks like the name has changed or it was bought by these guys... Perfect Resize 7.5 - onOne Software