Aperture and Lightroom manage photos very well. I've switched from iView Media Pro (version 2.5 was the last one I've actively used, I think) and Aperture is lightyears ahead. No more corrupted links to images in the iView library, no more saving the database, it just works. You can download a trial version. Aperture allows you to store backups of your photos on external drives (arbitrarily many) and manages those backups for you. It's very neat.
Ditto for Lightroom which I don't like personally, but I know it's a capable app. Adobe offers a demo version, too.
If you are searching for Aperture Lightroom, you'll find many threads on which one is better, but really both have their strong points and each app appeals to a different type of person.
But beware, these are pro apps, i. e. not iTunes. They are easy and intuitive to use if you know what they can do. But their feature set is quite big.
So one thing you can do with these apps is edit (non-destructively) and then you decide you would like to photoshop an image. Aperture creates a rendering of the file and groups it with the original in the library. Once you hit save in Photoshop, the edited version is in the library.
PS Aperture and Lightroom only manage photos, they do not manage videos and other `digital assets.'