Ballard was best known for books like the autobiographical Empire of the Sun (turned into an excellent movie) and Crash (also made into a movie), though I first discovered him with The Drowned World, via recommendation from James Gunn.
Ballard was a master of bleak worlds, almost always expressing an anti-technological view, one of the first to bring this perspective to SF. Though these views are pretty much antithetical to mine, I was nonetheless moved and impressed with his work, and he influenced how I write. And without him, SF would be a different creature today.
Best,
Chris