Are you having megapixel envy each time you walk by the camera section of your favorite electronics store? So do I. But, do we really need more and more pixels? The answer depends on what we intend to do with the images.
First, a quick definition of megapixel:

Megapixel is a technical term for "million pixels", where a single pixel is the smallest unit of color that a camera's sensor is able to capture. The more pixels in the sensor, the sharper the image a camera can reproduce. Note that some camera specifications abbreviate megapixel as "MP".

Determine Image Use

Now then, how many of those pixels do we need? The first task in answering this question is to determine how we intend to use the images. We are mainly concerned about uses that require a high resolution digital photo. Putting a photo on the computer's screen requires a low resolution image, so any camera is sufficient, if this is our only intention.
The most common need for high resolution photos is to print or develop pictures. Let us then focus on putting pictures on paper to answer our megapixel question.

Determine Largest Print Size

The second task is to determine the largest print size we would like of our photo. Sure, it would look cool to have poster-size images all over the house of our sweetheart, but are we really going to go through that expense? I assume for most of us, poster size prints fall into the "rarely or never" category.
Having ruled out extreme sizes, we have the three most common photo sizes to consider. According to online photo labs, the following minimum resolutions are sufficient to produce high quality prints:

• 4 x 6": 640 x 480 pixels (0.3 megapixels)
• 5 x 7": 1024 x 768 pixels (0.8 megapixels)
• 8 x 10": 1536 x 1024 pixels (1.6 megapixels)

I know from personal experience that my 3 megapixel camera is as low as I want to go for an 8 x 10" print; any less would start showing pixilation at close examination. Based on this experience, I suggest doubling the above megapixel recommendations when buying a camera.
This exercise has taught us that if we only want 4 x 6" prints, then 0.6 megapixels are sufficient. Most digital cameras start at 2 megapixels, which is sufficient to produce quality prints up to 5 x 7".

Focus On Other Camera Features

Now that we know the minimum megapixel requirements for our needs, we are free to focus on other important features of the camera such as lens quality, color reproduction, optical zoom, body size, etc.