This makes me very happy. I am in the overwhelming minority of professional photographers who don't use Photoshop, but I have happily been using Pixelmator since it launched.
Depending on your photography style, you should definitely consider Aperture, particularly now that it's so much cheaper through the App Store (US$80). I used image-editing software for my photography for a long time, but I have moved almost entirely to photo-dedicated apps like Aperture and Lightroom.
I actually do use Aperture to import RAW's (I bounce between that and Lightroom, but I find that Lightroom seems intentionally limited to entice you to use Photoshop).
I don't really post-process my images; they're controlled studio setups (mostly nude fine art). I also am not anti-Photoshop, if it turns out that at some point I need to use it for something, I'll buy it (I'm just happy that for the few years so far I've been doing work I haven't needed it).
I've used it in the past, just not since making a go as a photographer.
It's more that I was still using film for all of photography school, and doing processing in the darkroom. Since switching over to digital a year ago, I haven't really adjusted my process.
