I shoot one of those big heavy DSLRs–a Nikon D300 to be specific.  Having high-end equipment makes many things easier to do.  There is a very small list of things that are made possible only by such equipment.

Beyond a certain point, the question of megapixels is unimportant with regard to getting quality images.  As FarmGrammy pointed out, the rules of many contests specify a certain image size in pixels, (they do this so that the images can be greatly enlarged or used in high-quality print situations, such as magazine covers, etc. that require enormous resolution.  If contests are important to you, you obviously have to have equipment that meets the criteria.  If that's not your plan, then pretty much any camera on the market today will take excellent pictures of which you can be proud.  

There is a saying among photographers that the best camera is the one you have with you.  It goes along with the idea discussed here that the person pressing the shutter button has as much to do with the quality of the resulting image as the camera they used to capture it.  If a camera is too bulky or complex for you to want to carry and use, then you'll leave it home and take exactly zero pictures.

At the CITR Retreat in September I saw a couple of Fuji cameras, some Canons, and a Nikon or two.  They were all capable of taking great photos.

Just my two cents.