Canon EOS 7D or Nikon D300S

Canon EOS 7D is 18 megapixel and Nikon D300S is 12.3 megapixel, does that make the canon EOS 7D superior camera than Nikon D300S?

The simple answer to your question is, no. Resolution is not the most important measure when it comes to evaluating cameras. In this case, the Nikon's lower resolution probably delivers better image quality at high ISO settings. However, the 7D might still be a better camera for you. That's mostly a matter of what kind of subjects you're planning to shoot. So tell us more about what kind of photos you're planning to take and why you're looking at these two cameras :)