[iPod Nano]

Hello, there! I'm not sure if you need both a Mac and a Windows Machine. I would run Windows in Bootcamp or Parallels. If you will be downloading stuff to your Windows installation, yes, get a virus scanner in Windows. But, you don't need one for your mac. There's not much to protect them from.

I would recommend the following:
- Microsoft Office ($$$), iWork ($$), or OpenOffice (Free). All of these are fairly compatible and work similarly. Personally, I like iWork the best, but it's your choice.
- A good mail client. Most are free. I recommend Postbox (postbox-inc.com)

I hope this helps. Post or PM me if you have any questions.