In a news article Detective Inspector Bruce vad der Graaf says:
If you are using the internet for a commercial transaction, use a Linux boot up disk – such as Ubuntu or some of the other flavours. Puppylinux is a nice small distribution that boots up fairly quickly.
Another option is the Apple iPhone. It is only capable of running one process at a time so there is really no danger from infection.
So what Operating System or device do you use when you do your online banking?