Thanks to iPhoto Buddy and Keyword Assistant, I've found myself using iPhoto for managing not just my photos, but also presentation resources and all kinds of raw materials - which just goes to show you how a decent tagging UI and better library management can turn it into a useful tool.
The obligatory screenshot
That's 4384 images, which I'll eventually get around to tagging with keywords like Marketing, Management, Business Plan, Motivation, Project Management, Engineering, HR, etc. Should take me some 20 years or so, considering the free time I have.
Heck, I've done stranger things.