Share 'Productivity 2.0: What helps you most?'

There are a bazillion (yes, I counted) web 2.0 apps that claim to boost productivity and make life easier. Truth be told, most of them just create more work rather than saving time. Have you found one that really makes a difference in your day? How you work? What is it? Mine is Rememberthemilk.com . The site itself isn't that great but their add-on for gmail and their iphone app makes my day a w…