Yea i think Photoshop is the weapon of choice for most of us. But the only prob is you have to buy it. If you don't have the $$ to buy or don't want to risk a hefty fine/jail time for obtaining it illegally, than there are a lot of free programs out there that do relatively the same.
well if you dont have the money to buy photoshop and want something better than paint, try downloading GIMP...if you need any help downloading, installing, or learning how to use it let me know...hope it works well for you