As someone whose whole career was in the auto insurance business, I view Uninsured Motorist and Under-Insured Motorist as the most important coverages on my policy besides Bodily Injury Liability coverage.
Why most important? Because UM and UIM is coverage for injuries to me and my family, not to others. As noted by other posts there is a large % of Uninsured vehicles. And when you add the equally high or higher % of vehicles covered only to the low state minimum coverage there's a high probability of the other party not being adequately insured to cover serious injuries they may cause. Yes, after the accident I could sue if they didn't have adequate coverage, but its doubtful I'd recover much, so I buy a high limit for UM/UIM equal to my Umbrella cov limit.
Why most important? Because UM and UIM is coverage for injuries to me and my family, not to others. As noted by other posts there is a large % of Uninsured vehicles. And when you add the equally high or higher % of vehicles covered only to the low state minimum coverage there's a high probability of the other party not being adequately insured to cover serious injuries they may cause. Yes, after the accident I could sue if they didn't have adequate coverage, but its doubtful I'd recover much, so I buy a high limit for UM/UIM equal to my Umbrella cov limit.