Notice, shingle rows are straight and shingles are laid correctly.  Look are your house or your neighbors and see if the shingle is straight. These are GAF Timberline HD Charcoal Shingles.

Weatherwatch is an ice shield that is used in the valleys that protect against ice damage. If you do not have this, you can end up with a leaky roof. Make sure if you are getting a new roof that you make sure they use this. 

Roof vents are important because they allow the heat to vent out of the attic in the summertime and save on electricity bills and keep your house cooler.