I get a distinct inspirational stimulus from reading the more-or-less classics. Kipling, De Maupassant, Poe and some parts of O. Henry; all the Frenchmen with whom I am familiar except Balzac; Fielding, The Tale of Two Cities, The Way of All Flesh. Balzac is over my head. Dickens, outside of the novel named, seems to me a caricaturist rather than a novelist. The Growth of the Soil I hold to be the finest novel I ever read. No need of prolonging the list. Reading them over and over, the books which most appeal to me, I always put them down full of a brave determination to write something as fine. That the resultant effort dwindles out discourages me only until I have read the book again. I know no better way to put yourself in the mood for trying to write good stuff than by reading good stuff.
Honore Willsie: I have read and studied current and classic writers constantly as training for my work.
H. C. Witwer: Nothing from either.
William Almon Wolff: I don't know that I can distinguish between classics and modern authors. I've learned most of what I know that way, I suppose.
Edgar Young: Can't say. Have read many of the modern authors and most of the classics. Also have read rather widely in Spanish.
Summary
"Classics," of course, is a variable term, but even when not specifically defined it serves the general purposes of the question.
Of 113 answering, 58 found the classics useful to their craft; current authors, 49.
Some benefit: classics, 10; current, 13. Yes: classics, 32; current, 21. Much: classics, 14; current, 13. All: classics, 2; current, 2. Little: classics, 11; current, 10. None: classics, 13; current, 18. Waste of time: classics, 0; current, 1. Harm: classics, 3; current, 4. Don't know: 17. Not classified: 4.
The tabulation is on both influence and value. From the answers one gathers that the classics are read for: the fundamentals, highest art, clearness, vocabulary, characterization, style; current authors for vocabulary, what not to do, modern style, popularity, short-story structure.