The level of liability limits that you opt for will depend on what sort of assets you have. If you have a substantial net worth, then 100/300/50 coverage is too low. If you're in a bad accident and cause a serious injury, the plaintiff's attorney will do an asset search. If he sees that you have multiple properties and were the CEO of a prosperous company, he probably won't settle for the policy limit. When in doubt, go for the higher limit.
I would recommend hanging onto the Medical coverage. Not only does that cover you, it covers anyone riding in your vehicle as well. It's also no-fault which means that it gets paid regardless of how the accident was caused.
Definitely go with "Agreed Upon" or stated value coverage. Actual cash value will most likely leave you coming up short in the event of a total loss. With stated value you know exactly what you'll get.
For what it's worth, I used to handle liability claims for the third largest insurer in the country. I dealt with everything from simple fender-benders to multiple death cases. I never once had a case where the plaintiff wouldn't settle for policy limits. Doesn't mean it won't happen - it's just unlikely.