If your pet became ill or was in an accident and you didn't have insurance, you'd likely kick yourself, unless you're wealthy enough to pay the vet bill yourself... I think if you can afford the premiums, it's well worth it. Check Vet Insurance - Home to compare with other companies. They have a lifetime coverage of $20,000 for each pet, and I don't think there's a deductible.

Purina is now offering pet coverage but I think the deductible is quite steep, depending on which policy you have.

Good luck with whichever one you go with!