Wow, people need to think out of the box, it wasn't long ago people were saying the same negative things about cameras in cell phones, or video games, or mp3 players. Phones can be charged virtually anywhere these days, our homes, our cars, even the beach if you get one of those solar chargers. If companies stop innovating because people are worried about battery life then what's the point of owning a smartphone? If Apple doesn't do it others will.
The uses for a front facing camera are more than just video calls too, just like the amazing things that can be done with the 3GS's compass enabled augmented reality apps, a front facing camera as well can bring in a whole new world of possibilities.
Is The iPhone The Key To The Future Of Video Chat? - iSmashPhone iPhone Blog
We probably wouldn't any apps at all if Apple thought like some here.