I had to do Zen and the Art of Motorcycle Maintenance for school, and did burn my copy afterwards. It had little to do with the quality of the book (though honestly I thought it was rather terrible), and more as a childish act of celebration over finishing a brutal exam period where burning something symbolic of the hell I'd been through just felt great.

For other books I'd toss in, Twilight for sure. And Gossip Girl is as you say basically soft porn, so that too I guess.