Diablo III players are now reporting their accounts being compromised. Players report that gold and items have been stolen. Blizzard suggest people get an account authenticator.

More: eurogamer.net

Cryptic, producers of Star Trek Online and Champions Online, has just announced that they had a security breach in December 2010 that allowed attackers access to their players account name, handle, and encrypted passwords.

"The unauthorized access included user account names, handles, and encrypted passwords for those accounts. Even though the passwords were encrypted, it is apparent that the intruder has been able to crack some portion of the passwords in this database. All accounts that we believe were present in the database have had the passwords reset, and customers registered to these accounts have been notified via e-mail of this incident."

Soure: http://www.crypticstudios.com/securitynotice