What photoshop program is the best to use for anime?

I need a good program to photoshop anime. Which program would be the best? Some one told me that Adobe Photoshop works, is that true? If so which one should i purchase? What other photoshop programs work?

Thanks)

GIMP <- it's free and pretty much the same, (just a bit harder to use)

Hijacking....

Which version of Photoshop is good to start off with? Is there a really steep decline in features the cheaper you go? Do those features even matter?

Photoshop is Photoshop..............

/facepalm