I searched around on Flickr to find some cool shots that demonstrated the important points pretty well:

• Selection

Since this is a long-exposure shot, a decent amount of time and planning had to go into this.

• Contrast

I love the contrast between the silhouette of the landscape and the deep red and orange sky.

• Perspective

The buildings all pointing towards the center makes this a really neat shot.

• Depth

The perspective here gives the photo a lot of depth.

• Balance

The skyline of Seattle has much more visual weight than Mount Rainier in the background.

• Moment

Where is moment more important than when taking a picture of an instantaneous flash of lightning?

• Lighting

This photo has really pretty lighting from the sunrise.

• Foreground/Background

The whale in the foreground vs the town and hills in the background is a really neat dichotomy.