There is a very good reason, and I heard it was given by Kernighan 
and Ritchie: "we assume the programmer knows what (s)he is doing". And 
there is a second reason: C is very tied to the hardware; it is lacking 
abstractions.

     The sentence can be compared to Ada's design rationale: "we assume 
the programmer is a human being" (meaning (s)he persistently makes 
mistakes). Maybe K&R never wrote that sentence, but I like it because it 
fits very well with the nature of the C language.

     unsigned u = -2; /* example */

     I am very admirative of how the Linux kernel is efficient and safe, 
but everybody knows that this is achieved by hard work of some of the 
best C programmers in the world. This is THE exception. I had 
experiences of big programs in C and my experience is that debugging is 
long (and probably never ended) and evolution is a nightmare.

     For me, the question is rather why choose a given language out of 
all available languages? And the reason is generally because the 
programmer feels more comfortable with one. It can be discussed wether 
the choice makes sense, but I don't see even why C should always be 
considered.

     Didier