There's no way in hell I'd buy serious productivity software on Steam though, because suddenly losing access to all of my productivity software due to some single glitch with my account on their end is just not worth it for me. YMMV, but I'm ok with Steam's DRM on games but not all software.
If I buy a BOXED copy of a game I expect it to work without any other need other than the machine I install it on. This crap about requiring an internet connection is ridiculous. I have the discs, I even have the key still. Yet it will not run because my connection is down or worse their server is? (and yes Steam has had authentication issues)
I can't verify this at the moment, but no one has corrected the other poster yet.
You also have to be online to download, install and launch a game for the first time.
That's a lot different from the DRM claim, I think.