Measured in Bitcoins, it was 550k BTC in 2011. Here is a list with the highest amounts in transactions to one address: http://blockr.io/trivia/tx

In USD it probably was the "Shit load of money!" transaction with 195k BTC (147 Mio. USD) in November 2013 http://www.coindesk.com/194993-btc-transaction-147m-mystery-and-speculation/