We waited so long past when we should have gotten rid of the penny that now a coin ten times as valuable is also worthless enough that we ought to get rid of it.

If we would adopt a policy of including local sales tax in advertised prices, skipping to whole dollars would be pretty painless.

The main reason to keep at least quarters is all of the various coin-op machines that are still in service.

BTW, the reason for wanting to get rid of the penny isn't so much the low purchasing value, but more that they cost more to make (~4c) than their face value, so the government loses money making them. The same is true of nickels.