That would depend on what editing you want to do, and how much you want to spend. You could argue that the 'best' photo editing software is PS CS5, simply because of how powerful it is. However, CS5 is overkill for a lot of image manipulators, who are more than happy to work with a watered down version such as Elements 10.
However, if cost is a consideration, you could argue that Gimp is the best software available because it's free.
Personally if I was just starting out and wanted software capable of meeting my immediate requirements, but which also had sufficient features that would allow me to learn and progress without having to upgrade, then I would probably go for Elements.