I'd prefer randomized 'hard disk seeking' noises; not the click of death, the sort of soft muted chirping you used to get from very large and slow magnetic media as you actually heard the heads seek back and forth.

In an alternate pinch, licence some item get sounds from vidoegames and do A B testing on customer satisfaction.

Interestingly, before making this change the line did use a simple "enter account your number" prompt that was followed by a consistent combination of little clicking sounds that seemed to indicate something was happening. I found that much more pleasant than fake key taping.