Sounds cliche and possibly like I'm pandering to the HN crowd, but Startup School. I quote it constantly - almost on a daily basis. It wasnt way more about soft skills than actual code, of course, but I find that to be more important.
Also, my best advice at any conference is to take notes. I took comprehensive Startup School notes, and reviewed them later. I never would have gotten so much out of it if I hadn't.