Google Desktop version 4 is now out of beta and is available in 26 different languages. Some new features include:

-Google Gadgets
You can save your gadget content and settings online access it from your other computers by logging into your Google Account with Google Desktop. You can also sync the To Do list on both your laptop and your desktop.

-Richer Google integration
you can now add some Google Gadgets from your personalized homepage into your Sidebar, or anywhere else on your desktop. You can also view upcoming birthdays with the Orkut gadget, see what?s popular on Google Videos, or access your Google Calendar right from your desktop.

-Personalize your desktop
-Improved indexing
-Easily add content to your web clips gadget
-Removing deleted files from search results

Google Desktop blog Via Google Blog