32 versus 64 bit reading list suggestions

[Richard Owlett <rowlett@cloud85.net>]

I switched from Windows when Squeeze was current and was working with a 
mix of 32 and 64 bit machines. To simplify my life I used and continue 
to use the i386 flavor of Debian.

I have two underlying questions:
  1. As everything I currently use runs fine, what would I gain by
     switching to amd64 flavor?
  2.What 32 bit utilities are there to identify the hardware capabilities
    of a particular machine?

I'm asking for recommended reading list to discover questions I should 
be aware of that I don't recognize I should be asking.

TIA