- Todo List (source code)
- GMail - read and write e-mails without leaving the homepage (source code)
- Google Talk - simple and fast, replaces MSN Messenger (source code)
- Google Reader - better than opening each web page/RSS to read the latest news/updates, you just need to add all of them to Google Reader and you can read them in one place, with a "hide readed" function. (source code)
- Orkut Mobile - this one I made myself, just shows Orkut Mobile site inside the gadget (source code)
PS: The background image I've chosen for my iGoogle is the sky, updated every hour!