Adobe Photoshop CS5
Unlike its predecessor, which didn't really offer much in the way of new features but overhauled its look, Photoshop CS5 (Windows | Mac) leaves the interface practically untouched to focus on major feature improvements.
The big changes include automatic lens correction, better high dynamic range processing, content-aware filling, "intelligent selection", and enhanced tools for 3D image creation in Photoshop Extended (Windows | Mac). More than three dozen minor tweaks were also made, small improvements--such as building a "straighten" function into the Ruler tool and pumping up Raw image noise management--that nevertheless dramatically cut down time-consuming procedures.
Take a video tour of what's new, browse the Photoshop CS5 Extended slideshow, or dive in-depth with our full reviews linked above.