David Foster Wallace's persona has existed, as has Infinite Jest itself, for more than a decade as a ne plus ultra for the artistic imagination, a point beyond which it is difficult to imagine humans still thinking in words, much less in fiction. Although I have not read Infinite Jest, its mere existence seems to have shaped my conception of literature—especially contemporary literature—in a significant way. It is impossible to make any kind of account of late 20th century American literature without considering DFW, without including him as a keystone of whatever narrative edifice you're building. That is not, I think, something one could say about many of the other sprawling postmodern omnibuses (The Recognitions, Giles Goat-Boy, The Public Burning, JR, the collected stories of Don Barthelme) which Wallace drew his original inspiration from. Even Delillo's Underworld or Pynchon's Gravity's Rainbow feel somehow replaceable—if Delillo and Pynchon hadn't written those works, they would have written other things very like them in size and scope. Infinite Jest feels more necessary, somehow, for understanding what postmodernism was and what it became. It feels unreplaceable, and completely unrepeatable.
David Foster Wallace's early death may come to represent a terminus for the type of novel Infinite Jest was, and the type of writer Wallace was as well. There will be books, like Danielewski's House of Leaves or even Mitchell's Cloud Atlas, that think as big and as broadly and as smartly, but I can't help but feel something has come to a definitive end this weekend.
As I said, I have not read very much of DFW's work. I read a few essays in A Supposedly Fun Thing I'll Never Do Again, and a few stories in Brief Interviews with Hideous Men. For more informed and intelligent commentary, please look here, to David Gates's appreciation in Newsweek, to Laura Miller's tribute in Salon and here, to my friend Herbie's post on her blog, Meek Adjustments. And please read Wallace's Kenyon commencement address, an extraordinary work of passion and insight.