Google's Picasa

picasa,
originally uploaded by The Skillster.

This is Picasa 2 from Google.
Its a nice picture managment and touch up program and has a nice gui.
You can do many things from backing up your photos to a picture DVD to ordering prints online and blogging about your pictures.
I give it a 4 out of 5, since it lacks batch tag processing/grouping and ability to upload to sites like Flickr. Get more info picasa.google.com