I am not sure why this discussion thread seems to be going out of its way to degrade the importance of the ABC machine.
Speaking only for myself, there are two reasons why the AB machine should not be included on the original poster's list. 1. It's a calculator, not a computer. A calculator requires human intervention various steps of a problem. A computer runs a program runs until it's finished. The AB machine did the former. 2. AB never finished it. I do not view this as degrading the importance of the machine. But I would also point out an earlier example of separating memory from processing (Babbage), an earlier example of using vacuum tubes for digital logic (cosmic ray counters); and a long appeal about why Judge Larsen and Remington's attorneys both may have been tragically wrong.