Cent.
And shift the decimal point six places so that it matches regular currencies. No regular currency is divisible to eight places. We talk about thousands or millions or billions of dollars or francs or euros, not megadollars or petafrancs. Millibits or microbits might work for geeks but not for average people.
The problem here is: You cannot produce more Bitcoins to cause inflation if they deflate to much (I guess thats what is done with 'regular' money).
What would you do if in a couple of years 1 BTC is worth $5000? You would have to pay $50 for your Coffee because there is no smaller value.