I have a fresh install of Ubuntu 13.10 with the latest Nvidia drivers installed. However, when I run steam I am presented with the following message:
steam opengl glx context is not using direct rendering
I believe this is something to do with not having the correct 32 bit library, however I did install the Nvidia 32 bit libraries when I installed the driver. Running Steam from the terminal I can see that Steam is failing to find the 'swrast' driver which it shouldn't be looking for anyway.