iPhoto to me is a mediocre photo viewer. I prefer ACDSEE or PICASA but these options aren't available to Mac users. One of the most annoying features in iPhotos is its ability to duplicate sets after sets of photos in the "Originals" and "Modified" photos. I am dedicating this entry to help combat this annoying feature and share with you, what I deemed to be the more "PC" way to manage photo library utilizing iPhoto.
1. Managing the source - after taking a serious amount of pictures from my trusty camera or (downloaded from the internet), I usually like to keep my photos in a dedicated location on my computer (along with my other important documents). By default, I never keep it in where the OS is suggesting me to (ie. Never in "My Documents" on PCs or "[username] - Documents" on OSX). I find my own location being a much easier way to centralize my files (music, photo, or docs) when it comes time to backing things up.
2. iPhoto - Turn off its ability to duplicate a copy into its "Original" photo.
Under iPhoto>Preference>Advanced, check off the box that sayings "Importing: Copy Items to the iPhoto Library". When you are importing, try to go through the iPhoto interface (File>Importing>) instead of dragging the source images by mouse dragging. This step will prevent your images from being duplicated into the "Originals". With this move, you'll find that the images are merely shortcuts to your source. (Its easy to locate the iPhoto Library Originals folder under iPhoto '06, for iPhoto 08, use this Show Package Content reference to get to the Originals folder.
3. Modified folders - I tend to avoid editing in iPhotos (I'd rather use Photoshop to edit the the source). However, in bizarre occasions such as dealing with iPhone's images (no matter how you import photos off of your iPhone, it automatically assumes a modified set is necessary). There is a quick way to fix the problem. Just simple right click on the photos you've just imported into iPhoto and select "Revert to Original". This will get rid of the duplicates in the modified folders.
If this is done right, when you right click on a photo in iPhoto, only "Show File" can be selected (while "Show Original" is gray'd out). Selecting "Show File" should point you right to where your source file location. Whereas the iPhoto default whould give you "Show File" as the modified folder and "Show Original" as the original folder. Boo...
*Important Warning: This article is assuming that you do not want to take advantage of iPhoto's ability to help you keep duplicates while modifying your photos. You are minimizing iPhoto's built-in protection to keep a duplicate in the "Originals" and "Modified" folders. I personally find this iPhoto feature extremely annoying as it triples the size of hard disk space. I am also assuming you've got a clean canvas to work with, meaning you haven't already gone ahead and modified a bunch of images in an old iPhoto library. If you are pretty far along in using iPhoto for its features and have modified a good amount of pictures, you'll have to just start from clean slate and make copies/backups of your "originals" and "modified" photos.