I am embarking on a corporate expose film that could get me sued. How much protection does an LLC really offer if I am the only person associated with it and how much more does it cost at tax time? Has anyone else filed an LLC for a film production and can relate some experiences?

I have never gone this route myself, but I know that most indie films in Europe are being made under the umbrella of a Limited company.
In John J. Lee's "Producers Business Handbook" he calls them Producing Companies.
I can recommend this book if you're interested in this aspect of film making.
It also says you need a lawyer, because as a producer, which you will be, you will enter into a lot of contractual relations with people and businesses. Makes sense.

If you say "it could get me sued", in what way do you mean that?

After advice from our acct. and atty. we are structured as an LLC.

If you are worried about litigation, Errors and Ommisions insurance may give you better protection than the structure of your business.

But to be on the safe side it's better to discuss your film with a lawyer who can advide on the best ways to protect yourself.

I was taught early on that it's cheaper to talk to a lawyer about your plan before execution that after when you're being sued.