I've been upgrading a lot of my lenses recently, and my old Nikon 24-70 lens was replaced with the new version of the Nikon 24-70. It's one of my least favorite lenses, but it's also one of my most used. While it's a great general-purpose lens, I find the focal range a little boring. To make a lot of images more dramatic, I either want to be wider or tighter.
The lens is fantastic. It focuses blazingly fast, it's sharp, well-built, and the vibration reduction works really well. The 24-70 range is perfect for probably 80% of the images you'd need.
In the minus column, the lens is expensive and it's even bigger than the old version.
In the end, if you're a professional Nikon shooter, then this lens is absolutely necessary. It's probably the first lens purchase you should make. If you can't quite swallow the price, I'd say the next best 24-70 is the Tamron SP 24-70mm f/2.8 Di VC lens which costs about half of the Nikon.