I've been going to OBX since I was pre middle school.....and I'm pushing mid life crisis now. OBX can truly be split into 4 separate areas and they have their own styles and experiences and pick based on your own preferences. Lets start north and go south.....
(Disclaimer.....this is not to insult anyone or their preferences....just my observations and experiences over the years)
Northern OBX (Duck, Corolla, 4x4 territory) - this area tends to be more upscale.....and more posh than the other areas. It's why my wife and chose to get married here (beach wedding). We almost got married at the Corolla lighthouse, but we wanted the sound of Ocean with us. It can be pricier than other area's, but the restaurants are fantastic. Traffic is awful on the weekends....barely tolerable during the week. Water temp can be lower than the rest of the OBX
Mid Area (Kitty Hawk, Kill Devil Hills, Nags Head) - This is the heart of the OBX and where most of the activities are. Restaurants/Rentals/stores galore. Beach is great, surfing/fishing is good. Most of the hustle bustle is here. You will find many of the conveniences of home in this area. Movies, chain restaurants, etc.
Hatteras Island (Waves, Rodanthe, Salvo, Avon, Buxton, Frisco Hatteras) - This part is truly my favorite. It's more secluded, less like other beach areas on the northeast. Less people, less to do.....More for the true beach lover. We pretty much sit on the beach all day and not much else. Get some fishing in, maybe take the canoe out on the sound. Avon seems to be the biggest town of them all, and the farther south you go, the smaller it gets.
Ocracoke island - This is for the Hardcore. I've done many day visits on the ferry.....and someday we'll rent down there, but it's about as secluded as you can get as far as getting there, but the harbor is lovely and I've eaten at a few good places.
As far as other NC Beaches I HIGHLY recommend Emerald Isle. It was very much like the OBX....almost a cross between the Hatteras Island and the Nags Head area. Only been there once many years ago, and dying to go back.
Never been to Holden Beach but I've heard it's very nice and compared to the OBX it's very affordable.