I have to agree and disagree with Brandi on this one but its all gravy

But IMHO, NC wouldnt have what is called a "Top Tier" agency that you would think of in LA and the tiers of agencies there. Our work here is more regional than local so actors are also pulled from ATL, VA, SC and so on.
STW is a great agency. I have worked with a few people from there and they have a good reputation.
Capital Artists though, I have not heard too much about so that may be one you want to further investigate.
But along with Brandi, other good agencies in NC (that I reccommend) are Legacy, JTA, Talent One and East Coast Talent.
Do be weary though as there are a lot of scam agencies in NC and in the region for that matter.
DO NOT sign with anyone asking for upfront fee's or stating you have to take their classes or use their photographers etc etc etc. They should only be making money when you make money.
I would check though to see who is working the most and what agency they are with. Just note that what agency may be good for one person, may not be good for you. I would shop around.