I've spent the summer reading The Stories of John Cheever, mostly on the beach. Some other memorable beach-reading experiences:
Ayn Rand's The Fountainhead: When I was seventeen, I was really taken in by the whole objectivism thing, as most impressionable youths are, I guess. Thankfully, my critical thinking skills improved in college.
Vincent Bugliosi's Helter Skelter. I read this sometime in college, maybe the summer between my freshman and sophomore years. I could only read it in the daylight because it scared the crap out of me.
May Sarton's A Shower of Summer Days. Another summer read during college. My memory is a little hazy on this one, although I do remember subtle lesbian undertones.
William Somerset Maughan's The Moon and Sixpence: Loosely based on the painter Gaughan's life. Not technically a beach read, but I read it when visiting Put-in-Bay, Ohio, one of the little islands off Lake Erie.
Katherine Anne Porter's Oh Immortality: I read this last summer while visiting friends in Myrtle Beach.
Jen Michalski is author of the novel The Tide King, winner of the 2012 Big Moose Prize, the short story collections From Here and Close Encounters, and the novella collection Could You Be With Her Now. Her work has been nominated for the Pushcart Prize. She is the founding editor of the literary quarterly jmww, a co-host of The 510 Readings and the biannual Lit Show, and interviews writers at The Nervous Breakdown. She also is the editor of the anthology City Sages: Baltimore, which Baltimore Magazine called a "Best of Baltimore" in 2010. She lives in Baltimore, MD. She tweets at https://twitter.com/MichalskiJen.