Photoshop CS6 <3 E-5
Just upgraded to Photoshop CS6 and must say I'm very happy with the new version. Almost like I had a new camera. Especially handling of noise in the 800+ band as well as manipulating shadows and highlights in raw are just great. The lens corrections are also very useful, use them on practically all 7-14mm shots and can now easily compensate for barrel distortion happening when you focus very close to the camera.
There are a couple of usability quirks like the way the new cropper works (but you can revert to the old version) etc, but other than that, highly recommended upgrade IMHO. Also seems to be a lot of new features compared to ole CS3, so a bit of learning to get the most out of the beast.
Happy photoshopping, Håkan