The 64 bit version of Office is finally becoming a better default option for many use cases, as the era of old-school COM add-ins and obscure third-party incompatibilities fades away. Excel x64 is also becoming a must-have for heavy spreadsheet users, as the 32 bit version of Excel 2013 seems to be a disaster of instability. Internally, we are running the 64 bit Office Suite across the board, and have yet to find a single problem. The stability and performance is notably better.
Despite the push towards subscriptions, many home and small business users still get their copy of Office when purchasing their computer as the OEM pricing is attractive, and the trial is bundled on most computers. Unfortunately, it seems like Microsoft still isn't paying attention to their web sites, and the download pages have effectively completely hidden any links to actually retrieve the 64 bit installers, despite what their own support articles says. The mystery Language and install options > Additional install options > Office (64-bit) link doesn't exist.
We have found an obscure workaround that is documented on various TechNet forums, and seems to fairly consistently work to find your way to a 64 bit download link. Additionally, once you grab the installers you can just store them on your network and re-use them for future installs (as long as you're not attempting to re-use the key).
In the above link, put your OEM Product Key after the token - with the dashes. Then copy the full link and paste into your browser. Voila! Your very own Office 2013 OEM x64 installer.
Your mileage may vary, and of course Microsoft might pull this down at some point so let's hope they get the hint and actually fix the normal install page.