At the risk of hearing, "I don't care how you do it up North." I think the east coast (NY, NJ, etc.) and Midwest (particularly Chicago) really know how to make amazing subs. That being said, I think Jersey Mike's makes a great sub here in the Triangle of North Carolina (Durham/Raleigh/Chapel Hill) that's consistant no matter what location you go to, which says alot. They're nothing like most chains, which don't have that homemade taste. Unfortunately, we have way too many chains here (Quizno's, Blimpee's, etc) and not enough individually owned mom 'n pop type establishments.
Thankfully there are a couple (mom 'n pop places) that make an amazing sub, so all is not lost. Those would be The Food Factory in nearby Cary on E. Chatham Street, with a menu that'll make you dizzy (http://thefoodfactory.com/default.aspx) and Roma's Italian (which also carries Lupo's Speide marinade from upper NY area) on Harrison just off of Main Street. Either place makes a great homemade huge