Coming late to this thread -- blame mouser for highlighting it in the newsletter
I've used a few graphics / photo editors over the years.
For all the proponents of The Gimp, it's always looked to me like the learning curve is way too steep. I have a copy but I've never used it for anything serious.
Sagelight -- the paid version -- is brilliant for photo work. The noise reduction and one-shot HDR functionality components are very new and have become indispensable to me already.
I like Xara Photo & Graphic Designer
for object removal but it's a vector tool with photo capabilities added in later and again the learning curve is fairly hefty. And it's quite expensive. But it has a big and committed userbase and the fact that it combines vector and photo capabilities in one package may be a plus.
Serif PhotoPlus: I've had various versions of this for ages and still use it -- particularly if I want to add text or do object extraction, layer-based manipulation or, well, anything that's about changing the content of a picture rather than just tweaking it for whole-image improvements. It's a good companion to Sagelight but they definitely complement each other.
The various free tools mentioned in this thread: there are good points to all of them but -- with the possible exception of The Gimp -- I'm not sure any of them really delivers on all the functionality you're likely to want. Sorry -- I think you may have to spend money.