Liability is a given; comprehensive<collision
Comprehensive means (mostly) everything but collision - hail, fire, theft, windshield cracks/chips, etc depending on your policy.
It's much cheaper than collision. Look at your itemized insurance bill.
If you can afford to cover the replacement cost of your vehicle, then statistically, you'd be better off if you get rid of collision coverage (unless you suspect your odds of getting in an accident are higher than average based on your demographics).
[edit: can't spell, or think]