Jeff,
Only a relatively small percentage of US universities require the SAT, although the most competitive schools almost always do. It is up to each US school as what score they would be looking for. the admissions decision will normally be based on a combination of classes taken, grades received and test scores (if required). Involvement and leadership also can enhance an application but are not the promary factors.
It will be important for you to choose 3-5 schools to apply that you feel you are qualified to be admitted to. One or two can be dream schools, one or two should be great choices but maybe not quite as selective, and one as a back-up choice that you are farily sure you can get in to.
Good luck!
Jim Crawley
"Ask a US Advisor"
jcrawley@els.edu