The Mt. Gox hack netted $500 million,
Bitfinex $72 million,
Bitcoinica $460,000,
Bitfloor $250,000
Bitstamp $5.2 million.
South Korea’s Bithumb hack last summer — the exchange that serves 75 percent of the South Korean market for bitcoin — resulted in tens of millions of dollars lost for the 30,000 customers affected.
Add if you know of others ..