I wouldn't call steam essential. I mean it is a good program, but it isn't the end all of gaming. In fact if I had my druthers I'd rather have no frame work around my games. (ala gog.com.) But I'm not complaining, it is the best form of DRM out there at the moment.
Chrome is a good browser, still has some issues. It doesn't work so well on lower end PC's. (Unless they've updated it somewhat since they came out.) I find myself using firefox more still.
I guess my question would be..what is considered essential? It seems to be different for each person. For instance take a webbrowser: Despite our love for Chrome and FF, IE is still the dominate one...I know people that refuse to use anything other. (Please no "OMG they still USE IE!" cracks...)
Personal taste is really big on the net as Camon and I show many times, heh.
I guess we'd have to break it down to what you have to have. Maybe steam would be essential if you want to play MP valve games? Hmm..
I know I think to much