Download Windows 7 DVD Image
The links are ordered alphabetically by language. Some ISOs aren't bootable but contain single installation files that can install Windows 7 from an existing Windows installation. The bootable images can also do that, so there's no real advantage in downloading the non bootable ones. All of the following links point to the official download servers msft-dnl.digitalrivercontent.net and msft.digitalrivercontent.net.
Microsoft makes updated disk images available on a regular basis. I also check the Digital River servers regularly, and keep this list up to date with any new finds.