I have a Mac too....do you use iPHOTO or just your PHOTO file?  I'm having a heck of a time trying to find a way to manage all my pictures.  I've lost a lot of the RAW ones so I'm going to have to start over making sure I get things organized properly.  I spoke to someone at Henry's Photog Store - she graduated from a photography school and suggested LightRoom...it's kind of expensive, but then again photography is a $$ hobby. I've used the editing on IPhoto - it's basic, not too too bad.....but it doesn't sharpen my photos like I'd like or need somethings.