Picasa is an user friendly photo organizer, viewer and editor. The program is able to scan selected hard drives, folder(s) or the entire computer, and all images will be displayed and ready to be edited or organized into albums and folders.
It can be integrated with your Google account and you can share or upload photos through their services (Google +, Google Drive).
You can create screensavers and wallpapers from selected pictures, collages, run as slideshow, batch rename, backup photos (burn on disc or upload to Google Account).
It has powerful editing options, especially built-in presets for different effects such as auto contrast, auto color, red eye removal, sepia, sketch and many more.
Also, you can tag images and people by name and location.
Conclusion: The program has a modern interface and includes many high quality filters/effects. Some features such as tagging and backup aren't very intuitive.
Picasa is available as free download for Windows 32-bit and 64-bit.