I use Debian sid, with the proprietary NVIDIA driver, version 325.15.
Whenever I start Steam, it says I don't have 32-bit libraries.
I've seen lots of "fixes" to this problem, but every one of them involves apt-getting the lib files, and I can't do that, because their version doesn't match with the driver version.
I've used Steam with those drivers before, but I don't quite remember how I got it to work.