His first two examples are well-documented but not surprising: Mary Karr, sure—she dated DFW; Don DeLillo—no surprise there.
But then things get interesting: Thomas Harris! And Bucher backs it up with a passage-to-passage comparison between Red Dragon and IJ that is simply stunning. One might even be tempted to call DFW a plagiarist (if not for the fact that he re-writes Harris with such idiosyncratic brilliance).
For the sockdolager, though, Bucher draws a parallel to the oldest of old-school Nintendo games. And, I have to admit, it makes sense.
(He also argues, persuasively, that DFW was sincere in this list he submitted for a book that compiled the top ten favorite books of various writers. I always figured it was a joke, and a rather snarky one at that.)