I find that C actually gets in my way compared to D when I am writing code with limited resources. The end result is semantically the same but with D I can avoid macros, inline asm is easier etc.
while this makes all the sense in the world to even a seasoned C programmer...
I've been doing it so long I could write macros in my sleep, and inline asm is a fun little exercise.
Though i absolutely agree, especially with someone newer, that could be a major road block. Might want to learn D just to be more efficient (even though I will never abandon my first love completely)
Also anything i want to be very fast on limited hardware i also use C and C only.
As for any hobby programming i do on the side, C is usually my goto choice, unless i want to be very esoteric.. following along the lines of: "The enemy of art is the absence of limitations."