I like this one from my colleague Mike Ormond: http://ieaddons.com/gb/search/?search=trafficify. It shows traffic problems for any UK address you highlight as well as speed camera locations (note this is UK only). Mike has used Azure to do his data storage and calculations.
I also quite like the Postpad accelerator allows you to clip text and send to a web-based sticky note that you can access from anywhere.
Anyone seen any others that they particularly like?
I seem to have accumulated quite a few, here’s the first page:
And here’s the second:
All of these should be available on the gallery of course.