Dennis Mangan has a short bit on what the fortune of Howard Hughes would have amounted to today, that spawned a couple of nice links.
Adjusted for inflation, John D. Rockefeller’s net worth is reportedly upwards of USD$ 663 billion.
According to the price of gold, the sesterce today would be worth $3.25, by the price of silver, the sesterce today would be worth $2.00, according to general labor rates, 1 sesterce = $0.50, while prostitute prices would set the PPP value of the sesterce at somewhere between about $15 and about $50. Various commodity prices would suggest a value of possibly $10.00. Differing methods produce a range in the modern value of the sesterce at somewhere between $0.50 and $50.00, seemingly rendering any conversion to modern prices problematic at best.
Another interesting metric is % of GDP.