You can make some pretty good stuff with MS Paint if you don't suck at drawing. sumo paint is a program I used a lot a long while ago.

Sumo paint is a good one.
If you're on chrome: https://chrome.google.com/webstore/s...e-ntp-launcher

gimp's quite good but a little slow

Gimp is good, but, obviously PS is better, well, that's for me.
Even though i could make textures in gimp with my eyes closed( not literally), imo PS is better, i'm not using it for as long as gimp, but, it just feels smoother. It doesn't lag as much as gimp. And, it doesn't have tablet lag. For example, i go crazy with my tablet and if i go outside the gimp window while my pen is pushed down, my gimp goes crazy and random lag appears. So yeah, i just went to PS and for some reason, i can draw better in it..

There is no "correct" answer... It's all about opinion.

If I were to say mine I'd say Gimp 2 is the best free-ware there is.
But that's because it's the only program I've got experience with.

Other than that, I'd absolutely say Adobe Illustrator, which I'm currently using.
Since you work in Vector resizing without quality loss is zero problem, but it's not free, and not easy to use at all.

Photoshop is also a sweet program, if you can afford it that is.

I thought i forgot something. Well, it was this

Just pirate ps see if you like it more.