Safari.

Speaking of speed, I recently subscribed to O'Reilly's Safari online book collection. It's pretty great (other than being a little slow). I was going to buy a reference book for probably $40 at the store. Instead, I subscribed for $10/month and have access to that book, plus four others (swappable every two months or so, I think). For reference books on technologies you already pretty much know,—and thus, don't really sit down and read—it's as fast as looking stuff up in a physical book. And there's no question where to go to find the quality, detailed reference you need, unlike on the web.