It should also be said that GIMP is limited to pictures that will be watched in a screen (computer, tv, etc), not for professional printing.
It is a great tool and has many of the features that the big cousin, Photoshop has...
Yet, I have to say that Photoshop is the best tool in my eyes Of course, it is very, very expensive but... It does have a smaller brother, Photoshop Elements, that includes most of its features but it is more reasonabled priced.
Before asking, do a search... if you don't find the answer, then ask The purpose of this forum is to help others in the community, that's why it's called Sitepoint and not Linkpoint. SP Guidelines - No fluff.
Also, if by editing a photo you don't mean to manipulate the photo like hell but improve it with contrast, WB, exposure settings etc. then the better tool for you will be Adobe Lightroom, its much cheaper than Photoshop & it is made for photographers intending to be the digital version of dark room unlike Photoshop which is the big daddy for anything related to images/graphics & not just photos.
You may take a look at ACDSee's products, and specifically their ACDSee Pro Photo Manager. It's an all-in-one solution for photo editing, managing, and publishing. It has just enough feature set a photographer would need.