Pesonally, I think that a state supreme court internship after your first year in law school is one of the best things that you can do. Yes, some first-year students get jobs in large firms, but you will have that opportunity after your second year. Moreover, it is after your second year in law school that you will want to work as a summer associate in order to secure a job after graduation. Getting experience in a big firm after your first year won't help you too much in gaining a summer associate position.
A supreme court internship is good for other reasons as well. It is presigious. It is a unique experience, one that you may not have again. As with other fields, future employers like to hire people with varying backgrounds; lawyers like to have people who know and have worked with certain judges. Best, it will give you something to talk about that would distinguish yourself from others with whom you will compete for jobs during OCI.
There is nothing wrong with working for a large firm. The time to do so, however, is after your second year. I would go with the state supreme court internship.