Whenever I help friends and family buy a new camera, they almost always turn to pixels as the dominating trade point. The reality is, that’s probably not the most appropriate measure of “bestness” and here’s why:
The metric most often used by camera manufacturers and marketers to tout their products has been pixel count. That’s a shame, but it was probably inevitable — it’s easy to measure, and consumers are used to the idea that more is better. However, the number of pixels is a measure of quantity, not quality.
This is a great article explaining in a mostly non-technical way why pixels aren’t all they’re cracked up to be.
Case in point: I can (and have) print a 30″ x 20″ from my eight-year-old 6.1 MP Nikon D70 that look great because it has a 23.7 mm × 15.6 mm sensor. If I were to print a picture at the same size using my year-old iPhone 4S with its 8 MP 4.54 mm x 3.42 mm sensor, it would look very noisy.