Now a weakness of having viruses on your computer could be that the address that you want to send the coins to can be modified before your PC displays it. IE you receive a PM and the virus changes all bitcoin addresses in your webrowser to their address or if you copy/paste it changes the addresses in the clipboard. So then when you THINK you're sending the bitcoins to the right person, it could actually be the wrong address. That is the #1 thing I would watch for.

I'm sure the trezor team can give you better descriptions, but that's my 2 cents