How much airflow do you need?

I plan on getting myself a case fan for my computer with over 100 CFM. This is a great amount of air circulation, but it will get loud. I personally don't care, I have a padded case. Fans that move so much air aren't typically used on home computers, they are used in large server rooms where noise isn't a problem. I plan on using this fan to bring air into the case, as I want a positive charge.