“The only real solution to this is to use operating systems and browsers that are not as susceptible to malware. Linux and OSX have shown a great deal of resistance to malware of all kinds.”
Totally agreed. Nothing is 100% immune, but most infections target the architecture of Windows specifically. It would be a safe guess that most of them modify the Windows Registry. Guess what? Linux does not have a registry. What is a poor virus to do?
Pretty much. The registry is the root of many ms-windows problems. That and the fact that so many users run as an administrator. With Linux, this is fairly rare except for certain really stripped down distros designed for netbooks. Similarly, OSX discourages folk from running as an administrative user. On my mother-in-law's Mac Mini, I don't think she even enabled the admin user.
Another major pitfall is the fact that the OS executes things based on their filename (.com, .bat, .exe, etc.). Linux and OSX has no such paradign. In order for a file to be run as a program, it must be marked as executable. This provides another layer of abstraction between downloading and running a program.
From what I understand Win 7 is better about it's succeptability to viruses, but that's just hearsay for me, as I'll never use it so it really doesn't matter to me.
As you said, nothing is 100% immune, because no matter what safeguards you have in place, you can't prevent a user from downloading something and installing it if they insist upon it, but the architecture of Unix-based system seems to be safer than the alternatives.