There is no difference between ATA & IDE
IDE stands for Integrated Drive Electronics & ATA stands for AT Attachment. You will most likely find that you drives are actually EIDE not just IDE.
So your friend is wrong, there are no ATA or IDE specific cables they are the same thing. ATA is the correct terminology, but everyone seem to say IDE. They are just different terminologies for the same thing. If, however you are using a 66 or 100 ATA hard drive you are better off using 80 wire 40 pin IDE/ATA cables so that you get the correct through put when using a 66 or 100 ATA enabled motherboard. For CD Rom drives just use the 40 wire 40 pin cables.