I've got a similar configuration and chose the i386 over the X86_64 because there are more workarounds with the X86_64 and very few applications that I found benefited from the advanced architecture.
Just to add to the puzzle, there's a glitch in the installer that MAY leave you with a i586 instead of i686 kernel. To avoid that, check out this thread: http://fedoraforum.org/forum/showthread.php?t=139751
There's also an official workaround in case it does happen: http://fedoraproject.org/wiki/Bugs/FC6Common
(see Common Issues)
Otherwise for the install, I'd try to use this site: http://torrent.fedoraunity.org/
which has the latest versions. If you choose another method from the Official sites, keep in mind that the programs you'll download are probably 6 months old and will need to be updated when you get online. So, if you have a fast internet connection, it might pay you to do a fairly minimal install and then add up-to-date programs as needed.