In this is iPhoto. WOW. The difference between the old version I had, and this one is pretty amazing. There are some advanced features: face tagging and place tagging.
The face feature is amazing. It detects and allows you to easily tag photos. I just tagged my dad in a bunch of pictures at once, by initially tagging him, and then it finding other photo's he was in. From there, it's a simple one-click to confirm he is in a picture.
It works about 80% of the time. Which is a great time-saver and interesting effect.