There was a "Today Tonight" segment on TV some time ago, it went on to show how evil hackers can simply cruise the streets and find a wifi stream, then sit outside your house in a car with a notebook and wifi hacking software and hack you. They showed how simple it was for a professional evil hacker to easily translate and steal valuable personal data from the wifi data stream. So, they (evil hackers) don't even need to place a trojan on your PC anymore.
I tell ya, it gets more and more difficult to protect yourself huh?