Internet security best practices - separate PCs?

Hi,  I am a newbie to this community.  I wonder about an approach to really separate personal data and files from internet activity.  I am particularly concerned about online self-service financial activity at the moment.  Understanding that nothing is perfect, and there is no substitute for vigilance, for changing (strong) passwords often, etc., what about the following;

Three separate PCs (I have one Win8.1 home PC today) to be used as follows:

  • "Data PC"   Not connected to the internet.  Not connected to any home network.  Storage of my data, files, photos, etc.  Has all thick client software apps for document/image creation, editing, etc.  Connected to a local printer, and that's it.
  • "Finance Internet PC"     Connected to the internet.  Used ONLY to visit known/trusted sites ... self-service banking.  Also used for email to/from an email address that is not used for any personal communuication.  Connected to a printer.  Loaded up with Norton 360.  No data files of any sort saved on this PC.
  • "Recreational Internet PC"    Also connected to the internet.  Used for social networking sites, surfing, email to/from acquaintances and others, but never used to touch financial sites.  Loaded up with Norton 360.

I read many posts saying this sort of thing is overkill, and that separate profiles on one physical PC are enough ... but suppose I simply don't want to trust software walls and want to instead rely on physical ones?

Thanks for all feedback