How do I install Steam 64-bit when package dependencies cannot be resolved?

Solution 1:

steam64 is just a virtual package for the i386 steam package of the same version.

By default, x64 Wubi (and normal?) installs don't have i386 support enabled, which is required by the steam package. To enable it, you can do this at a terminal:

sudo dpkg --add-architecture i386
sudo apt-get update

As of this writing, the steam and steam64 debs in the software center are out of date (1.0.0.26) and contain Beta warnings. These warnings have been removed in the .deb on the Steam site (1.0.0.27).

Solution 2:

All right, I've figured this out.

What you need to do before trying to download Steam is to update your system. You can do this two ways, either by going to the top left hand corner and clicking the dashboard icon and then searching for Update and using it; or, manually:

sudo apt-get update 
sudo apt-get upgrade

Afterwards, do not install Steam from the Ubuntu Software Centre. It is extremely buggy, and in most cases will not work for you. (I had everything up-to-date in terms of update, yet it kept giving me the same problems.

Install steam from its homepage: Steam. You should be good to go.