You asked about a program that does good editing and said you have a Mac. I would recommend you start with iPhoto, which came with your Mac. It does all the basics very well, is easy to use, and you already have it.
Once you have gotten past the basics, if you want to do more on the computer, go to our Forum titled "Digital Post-Processing & Workflow". Depending on what you want to do, you can get into specific dialogues as to whether your next piece of software should be Aperture, Lightroom, Photoshop, or something else.
But don't sell iPhoto short, it should be able to handle your needs quite nicely while you focus on learning to take advantage of your new D7000.