I don't like the argument that voter fraud is so infrequent that we don't need checks to ensure the security of the process. If we don't currently have checks in place, doesn't it stand to reason that we possible don't see a lot of fraud because we don't have a good mechanism to detect it.
Voter fraud disenfranchises voters more than having to prove your identity ever would. As long as there is a mechanism in place to have free/low cost mechanisms for confirming identity I don't see the harm in requiring an ID. I don't buy the idea that it would be a hindrance to voting any more than our current registration process. In fact, I'd prefer that voting required some form of commitment to the process. In my opinion the small number of people voting is not the problem, but rather the small number of INFORMED people voting is.