I started to use two tools which dramatically increased my productivity. That's a good thing to work with so many different people, there is almost no day you do not learn something - even if it is only a super simple tool.
#1 - "TotalFinder" - It simply adds Tabs to the Mac OS finder and makes it a lot more convenient to use multiple finder windows..or tabs..whatever. It also adds a Dual-window feature to the finder, something I really like about working with Windows 7.
#2 - "iAWriter" - A tool to create text. Not more, not less. And that's exactly what I love about it - no danger of procrastinating in choosing fonts or playing around with grids and layout. Just text.
