12 amazing productivity boosters

I just read an interesting article on pcworld.com entitled, "12 amazing productivity boosters." While I think it lists some good productivity tools, it got me thinking: What makes you productive?

For example, does a good to-do list make you productive? What about a calendar? While those are most often associated with productivity, I think the productivity gains from a better to-do list or calendar are often minimal. In my opinion, productivity tools are those which help you work faster or easily accomplish difficult tasks.

For example, one of my favorite productivity tools is Dropbox, which lets me access files from any computer without emailing files around or using remote desktop. How about you? Do you have a favorite productivity tool? Feel free to share in the comments.