A digital photographer's heaven
The more I use digiKam, the more I appreciate it. I can't imagine managing my photos without it! (sorry windoze user :P )
The one feature the really struck me was the advanced search features. In digiKam you can create complicated search queries and can store the resulting photos as a group! Neat...
In the many chronologically arranged albums I had, I tagged the pics I liked with the tag "Cool shots". Then to get all the cool pics at once, all I had to do run a search for all pics tagged "Cool shots" and it would show up all the nice pics all at once. The combinations are endless. For example, you might want to look at only the "nice" pics from the shots of your cousin you took.
One more great thing about digiKam is all its cool plugins. One really utilitarian plugin is the red eye removal plugin. It does work.