A lot has to do with your end in photography. In journalism, it is not OK to touch up photos, to clone out things, etc. While you can adjust levels, reduce noise and tweak shadows, your photo should be appear as is and not altered in a significant way.
At the same time, for most other purposes, it isn't a big deal to do some massaging of the photo. The problem that I have is not that these things are done, but they are done in such a heavy handed way as to look odd, silly or garrish. HDR photos can be very striking, but more often, they look like they come from a video game.
Last edited by Rondec; 02-23-2010 at 01:27 PM.