Bristol_Jonesey
I used to think this way.
But in my opinion, provided you're careful about which sites(!) you visit and have suitable anti virus/malware software installed, you stand as much risk of infecting your machine as you do from plugging in a usb stick.
I have seen first hand the havoc of virus distribution using removable media on computers that are never connected to the internet. Indeed in my company Windows computers that are not connected to the internet had a much higher rate of infection until we introduced a policy of installing anti virus software and keeping it up to date. Another good tip is turn auto run off for removable media.
As a result I am far more paranoid about USB sticks than internet connections.
My previous DAW was connected to the Internet full time and used as a general purpose browsing as well as authorizations for several years without problems apart from some low level malware like tracking cookies, however my new DAW is connected but only be used for selected sites for downloads and authorizations etc. The other stuff will is done on the old machine.
You can say I have been lucky, but with viruses, most of the time you make your own luck.