Last year, Hot Rod reviewed plug wires and said there were next to no power differences between them. They also compared them for durability, price, fit, pull torque, etc. Check out the article on Hot Rod' magazine's site: http://www.hotrod.com/techarticles/67038/index.html
My old spark plug wires were Accel 8mm's. I had them on the car for 3 years, put maybe 5000 miles on them, never drove the car in the winter or rain, and they started falling apart and terminals started corroding.
My new wires are MSD 8mm's. I didn't think it was worth the extra money to go to a bigger wire.
MSD I believe have one of the lowest if not the lowest resistance per foot if that helps any. I have them on both of my stangs and am really pleased.
Kevin