Basically any program that have the tools that you need for the things that you want to do is good. Photoshop will pretty much cover all your needs, but there is no point buying it if you can settle for what gimp or Mspaint offers.

Remember that having an expensive program won't make you a good artist, years of training will. Having the right tools for the job just makes it a little bit easier for you, and someone that knows how to paint can do amazing things even in the shittiest of programs.

even if the programs aren't really comparable I will say Photoshop is the best one. Each program has their own fields but photoshop is really strong on many.

thx for repeating what I just said lol

Yeah I'm gonna go with the latest version of photoshop cs5

GIMP is the best by far.

Photoshop won't cost a cent, if you know how but I hate the layout of Photoshop.

GIMP has the same tools and is user friendly.

Anyone who says anything other than photoshop is kidding themselves.

There's a reason it costs an arm and a leg.

I have photoshop CS5 and it's amazing, you can make all, it's fantastic.

Photoshop and Artrage.

Have both.
Both awesome.
Artrage is more ...
Advanced though.

best free = gimp
best paid = photoshop
deal with it :P

You obviously haven't heard of Pixlr Editor. It's free and very easy to use.
(If you're looking for more professional software, get photoshop).

Stop! Didn't I answer already? Who the heck deleted my comment.

Photoshop > GIMP. I don't know one user who makes over-the-top art using only GIMP + tablet. All the big dogs (e.g. famous artists who make some 10k $ x times) use Photoshop, maybe Illustrator, maybe Corel sometimes. And then there are some people who make 10k $ once a half year or year from art, who use Mypaint, maybe Gimp, maybe some other stuff. Tho I doubt they really earn that10k $ from digital, otherwise they'd buy PS.

That's it. GIMP is lacking to PS. If you want to draw like a BOSS, buy PS like a boss (I don't wanna you going to the prison, especially if you're in US, where it's strict)