I was taking a bunch of pictures today around sunset (mmm... long shadows), which meant I didn't have full daylight to illuminate things. However, I foolishly insisted on using my long zoom lens (300mm on my camera == 450mm on a full-frame camera). In practice, I only got really sharp photos if I braced the camera against something (e.g., a light pole) or cranked up the sensor speed such that I could do a 1/1000 sec exposure. This is with my six megapixel Nikon D70.

Pseudo-moral of the story: unless (or perhaps, even if) you've got some kind of optical image stabilization, once you get to six megapixels or up, you're in a world where even minute jitters of your hands directly translate into not-quite-sharp photos. Left unchecked, this may create tendencies to blow money on over-built tripods or a wide variety of other senseless camera accessories.

Buyer beware.