CryptoLocker. Heard of it? Maybe not yet, but you should be taking precautions against it. This tricky little trojan virus will encrypt all the data on your computer and then hold it for ransom. Charging you $300 to get the key to unlock your data. Here are some articles and tips for protecting yourself.
ReadWrite: How to Fight CryptoLocker
Krebs on Security: CryptoLocker Crew ratchets Up the Ransom
Wikipedia: CryptoLocker details on Wikipedia