Most programming books I'd recommend have been repeated a lot recently in news.yc, so I'll add a couple good ones on usability: The (Psychology|Design) of Ever

Most programming books I'd recommend have been repeated a lot recently in news.yc, so I'll add a couple good ones on usability: The (Psychology|Design) of Everyday Things, by Donald Norman (it comes under both titles; 'Psychology' is an older edition.) Don't Make me Think, by Steve Krug And a timeless one on writing: The Elements of Style, by Strunk and White