for the average user photoshop is way over the top. paint.net is an easy to use FREE app perfect for touching up or making some fancy signatures.
There are loads of plugins for it aswell:-
Do you know what nemesis means? A Righteous infliction of retribution manifested by an appropriate agent. Personified in this case by an 'orrible **** me!!
adobe is by far the best, it can be compicated but its like anything else, once you get usto it, it's easy to use!