Iowangle, travel insurance might also cover rentals... since the loss/damage/collision expenses can get so high if something bad happens on a trip, it's best to check everything out to be sure.
Credit card coverage against rental loss/damage/collision can be primary or secondary... primary meaning that all costs are covered without involving your own vehicle insurance, secondary meaning the CC will cover what your own vehicle insurance won't, which might be the deductible. Primary CC coverage is probably best for those that don't own a vehicle, and don't already have insurance but check out all the possibilities.
Also some types of vehicles won't be covered by the credit card, like luxury cars, trucks, and business use only vehicles might not be either.
The rental car business has had some pretty bad stories in the news with staff overlooking dents and scratches during the pre-rental inspection and then noticing them when the rental's returned. In that case the credit card coverage against the scratch/dent could be a $1000-plus moneysaver... good luck out there.