Aperture will get the job done brilliantly. iPhoto isn't gonna make it though. It has to swallow everything into its own library, and you can never figure out its folders. Talking about a photo black hole.
EOS 40D+BG-EN3/350D/17-40 f4L/70-200 f4L IS/50 f1.8/18-55 f5.6/MacBook&ThinkPad
You can set Aperture up to store masters in their original location, which means don't copy anything. Or you can specify another location to put you masters, say User/you name/Pictures/Photo Library/.
But all you versions, previews and thumbnails are always in the Aperture library, but they are rather small in size, so it's not really a concern here.
EOS 40D+BG-EN3/350D/17-40 f4L/70-200 f4L IS/50 f1.8/18-55 f5.6/MacBook&ThinkPad