IMHO as someone with a BA in Economics, I think it's a great major for a prospective law school applicant. I also think math, philosophy, accounting or finance would be as well. That said, from what I understand it's not worth going to law school unless you can get into one of the Top 14 schools, which is very hard to do.
EDIT: I'd also discourage you from a double major because of the time factor involved. I doubt testing out would be held against you if your LSAT is very high, except perhaps at the top schools.
EDIT: I'd also discourage you from a double major because of the time factor involved. I doubt testing out would be held against you if your LSAT is very high, except perhaps at the top schools.