what do you want to DO in post-processing?
I used to use Photoshop in "the day" to edit photos.
Switching to a Mac from PC, I stuck with Photoshop as my main "go-to" for editing. and would use iPhoto to "store" the photos.
I then got into using iPhoto for most editing but felt it was lacking. It was a simpler Photoshop. Most of what I needed could be done in iPhoto but, like PS, it was mainly a one-off process. (yes, I can use Actions in Photoshop but that requires building an action and not too easily to undo or change some parts of the action when a few adjustments might be needed from the action)
THEN last year I opted for Aperture. this took the ease of iPhoto (and the DAM, yes I know you don't need/want that) and the simple nature of it but expanded the editing and ability to copy a setting and flow it over to a bunch of photos taken at a similar time.
Last year I got into RAW and more manual control of photography. I'd guess some of the last BIGGER photoshop edits happened about 4 years ago, when my son was 6 months old and I was dropping in type and adjusting perspective and doing some thing like that. I still like that but don't really bother with that.
Being a graphic/web designer by day, I am opting for ease with my photography edits and more family time.
Aperture and Lightroom are similar (please don't bash me on what one can/cannot do) and easily what most edits can be done with once you understand the limited masking that can happen. I chose Aperture because it was cheaper at the time (pretty sure) and I could easily open iPhoto libraries and 'test' it out.
Not sure if any of this helps.
