A better question to ask is where the processing occurs - in the camera or on your computer - and how much control you have over each of those processes.
This is well beyond the point of discussion, but if you want to go this way then question is not where
, but who
. Machine (automated processing via in-camera software which you can customize only to a certain degree) against Human (via image editing applications, over which you have full control). App type is ultimately secondary -- Picasa, Gimp, PS, Irfan -- except for pros, common tasks that most amateurs need can be done in all of them.
Even more philosophically, in wider term, it becomes question of AI versus Human brain. Smart self-driving cars, automated voice-recognition telephone menus (is there anything more annoying than this?), or -- image editing. Machine will always lack human intuition and be limited to what/how it can learn by its programming, but it can only get better with time.
I like steventy comment about having fun with post-processing though. It's a huge factor because there is level of pride in it ("look what I've done" - compared to "look what dumb machine did").