Bitcoin/Bit/Satoshi is the way to go. Each range of 4 decimal places will cover 10,000 units, which is easy to remember, and the names are easy to say. And look at this beautiful little thing below. You can express this whole naming scheme in two lines!
1 Bitcoin = 10,000 Bits
1 Bit = 10,000 Satoshis
Simplicity. Marketability. Roll-off-the-tongue-ness.
The nice thing with the 10,000 factor is, we have already another one for the upper side (although it sounds more slang than offical):
1 Pizza = 10,000 Bitcoins
"That whale owns a Za".