Shotwell is a free open source image manager for Linux, competes against F-spot, and is an alternative to ACDSee. Shotwell displaced F-Spot as the default image manager in both Fedora 14 and Ubuntu 10.10. You might use Shotwell as the next step up from IrfanView when you have a huge number of images.
Download Shotwell from yorba.org/shotwell/.
0.8 has video
Ubuntu 10.10 installs Shotwell 0.7.2. You can connect the Ubuntu Software Centre direct to the Shotwell software repository and download 0.8.1. 0.8 adds video, a great step forward with so many modern cameras also taking video.
There are other new things in Shotwell 0.8. Some things happen automatically in the background instead of you pressing a button. There are some upload-to-fashionable-web-site options but not for regular Web sites. A good Web based image manager would easily replace Shotwell because it is so easy to run Web applications on any computer.
Classification by keyword
F-Spot and Shotwell let you tag images with keywords for classification. F-Spot lets you add tags as children of other tags while Shotwell has the feature listed on the roadmap for a future release. You could create the tag family then add the names of your family to family. You could then select every image containing a member of your family or photographs for specific family members. If you had Tom as a member of your family, you add only the Tom tag to identify an image as both Tom and family. In Shotwell you have to enter Tom,family to get the same result.
Shotwell will automatically load all the images from a directory and classify them by year and month. This is helpful for your original images. It is a pain when some of your images are edited and are filed under the date they were edited. Test the initial load options to make sure they do what you want.
I found the best way to protect your original images from damage is to manually copy them from the memory card to disk then let Shotwell import them.