best editor
I usually use GIMP or Photoshop. They are practically the same, but once you've used both a bit, you'll notice that some things, although they can be done in both, are much easier in one or the other. Therefore I usually switch between the two to make anything. :D
Of course, Photoshop isn't the easiest to aqquire and it's expensive. The GIMP is a great program to use instead of it. Like I said, it can basically do anything Photoshop can do, some things easier some things slightly more complicated.
It alle depends on what use you have for it. Adobe Photoshop can make some amazing results wheter its for creating amazing picturs, adding effects to pictures or doing some standard image editing.
From what ive heard and understood from the other posts in here, gimp does the job quite okay too.
paint is rather silly, not meant in any offensive way ofcourse :) but it doesnt have the capabilities that photoshop have.
Another program thats quite nice is autodeskĀ“s 3d studio max also known as 3d max or 3ds. Its not a program for image editing, its more like making some cool stuff in it and making the finishing touches in a program like photoshop.
but in the end it alle depends on what you are going to do. 3ds is not really the program for image editing at all, but if you are going to create wallpapers or just like being creative then 3ds is quite neat :D
Good luck in finding what you need :)
The Paint is cool if you know to use: How to paint Mona Lisa in MS Paint