I think if we try to draw a line between what techniques are classed as "retouching" and what are "manipulations" we'll be arguing 'till the cows come home.
If this new Gallery is going to be created (which, from the current state of the poll, seems likely) how about a simple "rule of thumb"?
Notwithstanding what you actually did to the image:
- If you clicked the shutter yourself - post it in Photography
- If you used stock images or a combination of stock and your own work - post it in Photo Manipulation
Just trying to make it easy for everyone...