I love iPhoto for my personal best-of archive, but use Adobe's Bridge and Photoshop to organize, preview, edit, add copyright and keyword info to my photos.
I've found that I don't have to do the keyword thing twice if, instead of adding these files from the Finder, I drag images to iPhoto directly from Bridge. Somewhere between these two applications, the keywords get recognised and added to iPhoto along with the image.
This also removes the need to save files with special names to ease finding them in the Finder. Next up, it would be great if Bridge Ratings and IPTC Core Location were recognised, too.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20060808032135119