For infrastructure technology, C will be hard to displace.

Twenty percent of all input forms filled out by people contain bad data.

Any editing, software work, and mail is done in this exported Plan 9

C is declining somewhat in usage compared to C++, and maybe Java, but perhaps even more compared to higher-level scripting languages. It's still fairly strong for the basic system-type things.

The kind of programming that C provides will probably remain similar absolutely or slowly decline in usage, but relatively, JavaScript or its variants, or XML, will continue to become more central.

From an operating system research point of view, Unix is if not dead certainly old stuff, and it's clear that people should be looking beyond it.

Obviously, the person who had most influence on my career was Ken Thompson. Unix was basically his, likewise C's predecessor, likewise much of the basis of Plan 9 (though Rob Pike was the real force in getting it together). And in the meantime Ken created the first computer chess master and pretty much rewrote the book on chess endgames. He is quite a phenomenon.