A couple of weeks ago I completed my PADI wreck diving certification and my Nitrox certification through Olympus Dive Center. They are a A-1 organization. The boat was probably the best I've ever dove from. Capacity seemed to be around 30ish, but there were only about 20 something divers, so we had plenty of room. There were ropes draped throughout the ship, which really helped walking around when the seas got a bit rough.
The salon was roomy, and the bathroom was the nicest I've seen on a dive boat - an actual toilet, sink w/soap, mirror, window....
The upstairs portion of the boat had 3 huge bean bags. They were phenomenal for catching a few winks while headed out to the dive site or on your way back (it took about 2 hours each way). They also provided fresh fruit after our dives and frozen popsicles. You had to bring your own food/drinks otherwise, but there was plenty of room for a cooler and for dry bags.
The diving was very good, as well. The Shipwreck Cemetery of the Atlantic. We dove 3 WWII wrecks, including the U-352 and a sunken Coast Guard ship. The wildlife was amazing. Loads of sharks - I saw a fairly big sand tiger shark, and you would not believe the size of the barricudas!!! Like 4 ft.long. There were lots of angelfish, lion fish. We even had a school of dolphins come up to our boat when we were anchoring at the U-352.
Also, the Olympus Dive Lodge is very convenient, clean, and super-cheap, only $25/night. It's also fun to exchange dive stories there at the end of the day. They have several rooms w/bunkbeds, so bring a sleeping bag or sheets/blankets/towels. It is pretty spartan, but considering the little amount of time spent there and the comraderie, it's definitely the way to go.
North Carolina coast is supposed to be the 2nd best wreck diving destination in the world - second to Palau. I was very impressed. The visibility wasn't that good when I went, but a hurricane had just been there one week prior, so it probably does have better visibility if it's not hurricane season.
Anyway, I just wanted to put a good word in for this organization. If you're interested in diving NC, this is the shop to use.