iPhoto imports, organizes, and does some editing. In addition, you can easily email images and make picture books right from iPhoto. I think on a Mac, this is will work well for many users who don't need Aperture/Lightroom-like power. I would guess that many amateurs (like me) use iPhoto and Photoshop Elements and cover the most common photographic situations.
EOS Utility and DPP will import, convert RAW, and allow some editing (although I don't do much with the EOS Utility other than put my name on my 1DMKII, i.e., I don't do tethered shooting). I do like DPP's RAW conversion and have become used to working with it. It actually keeps me from making a complete shift to Aperture (as well as Aperture's complexity).
