Who should become the new faces on US coins and money?

The way the country's going I think we need something like this:

At the end of the 20th Century there was a BBC programme about the Greatest Briton with viewers voting on their choices.

The last ten had a programme devoted to them with a celebrity endorser. I remember Shakespeare, Brunel and Elizabeth I making the last 10, (along with Princess Diana, who wouldn't get a mention now,) but the winner was Winston Churchill.

America did a similar exercise and came up with Ronald Reagan, when Briton's were asked who they thought the greatest American was they said Homer Simpson.

Personally I would go for FDR, but ax he's a president he's most likely already on currency.

Failing that how about someone like H L Mencken, if nothing else he's a wonderful source of quotations?