Thanks for your question. I think if you are not going to make big posters on a regular basis, you should not need to worry about megapixel because you can not found the difference when looking at images on a screen or when you have printed them out.

I think you should buy the 30X zoom. You can get much better detail and zoom in much more and get much better pictures with cannon 30X zooming camera. In this camera, the texture of different objects with a 30X zoom. You can not do that with a 16X zoom because the amount you can zoom is largely limited I think.

We know, when we use a camera is 14MP, each picture of the camera will be like 2MB in size. So many people try to say that a camera with more megapixel is a better camera. They say that because they know that the most of the people only know about digital cameras so they are trying to spread this among the general people.

I again say that the difference of 16 mega pixels and 12.8 mega pixels is a big difference. But 30X and 16X optical zoom are a big difference I think. So, you should buy the canon that has 12.8 megapixels and 30x optical zoom. Hope you find your answer.
Thank you