First, let's look at C. After A and B (yes, really), C represented a huge leap in capability of writing computer software. The constructs were concise, yet powerful and flexible enough to represent anything. Over the years, C has evolved - and morphed (some might say polymorphed). (Yes, hold the groans.)
The UNIX operating system was the first one developed in C. It is also probably the most widely used computer operating system in the world - if you include Mac OS X and all Linux flavors under the UNIX umbrella. You may not realize it, but handheld devices, even computer printers, and more often run some flavor of UNIX. The list is literally endless.
As one of the inventors of C and UNIX, it is extremely difficult to overstate Dennis Ritchie's contributions to all things electronic at this day and age.
So I think, in retrospect, that 2011 will go down in history as the true end of a large part of the second era of electronic computers. The first era, of course, is the vacuum tubes up until the electronic transistor and silicon chips - the second would represent the proliferation and "ubiquitization" of computing devices. As I look around my room, what computing devices do I have? iPhone, Macbook Pro, Comcast remote control, Motorola Comcast cable box, NEC TV, Sony iPhone dock clock radio, Panasonic VCR, and Toshiba DVD player, plus our Panasonic cordless phones. That's just in the bedroom. You would find that many such devices run an embedded UNIX, and even if not, that the software/firmware for the devices was written in a language with C roots.