As was stated, Aperture is for photos only. Photoshop can be used to edit all types of image files. Photoshop is also outstanding for the advanced editing of photos. (+1 for Photoshop)
Photoshop cannot be used to organize your photos. It simply opens an image that you point it to the way a word processor opens a document. Aperture has a library that allows you to organize your photos. It has the organizational abilities that are missing from iPhoto. You can create hundreds of albums and projects AND IT ALPHABETIZES THEM so you can actually find what you're looking for (unlike iPhoto). (+1 for Aperture)
I use them both. I maintain my library w/ Aperture, but edit w/ Photoshop as I find Photoshop much more comfortable to work with. I came from a PC background and used Photoshop on the PC previously, so this probably accounts for my bias towards Photoshop.
Shop for your Apple, Mac, iPhone and other computer products on Amazon.
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.