Oooohh, I love the OB! My father has a house there and we stayed there many times/years before he built his house. First you need to decide where on the island you want to be. Very south is Hatteras Village. There is a small grocery store, pharmacy, artsy gallery shops, general store, boutiques, pizza place (good one),the ferry landing (ferry from Okrakoke Island which you get to from either Hatteras or the main land at Cedar Island Ferry landing), and right by the ferry landing is a complex of shops including clothing, kite/toy stores, restaurants etc.
Further up is Buxton and the 'wide' part of the island. There are a few shops, ice cream parlor, the lighthouse, the point (where the lighthouse is and people fish or check out the two different currents meeting in the ocean there)
On up is Salvo, Rodanthe, and other towns I am not as familiar with although the surfers usually hang with Salvo and Waves.
There are small restaurants scattered here and there, often changing year to year as someone else tries to make a go of it.
It is more commercial than it used to be, but it is nothing like Myrtle Beach or Panama City. There are great beaches to fish on, a couple of piers for fishing (although I have never been on them, many tackle/bait shops, deep sea fishing excursions, beaches that allow 4x4s (DONT try it without them though! The sand is much deeper than anywhere else I have ever been and even 4x4s get stuck sometimes)
The island has a Native American Museum, a tiny airport, three grocery stores (until you get to Nags Head. In Hatteras Village there is a Red and White-tiny grocery, Conner's is further north- I think above Buxton and a Food Lion further north.) the lighthouse, shops, fishing, fishing, fishing, kite flying, Okracoke Island (shops, lighthouse, Coast Guard Museum, shops, restaurants, a wild pony enclosure, bicycle rental- 45 min. ferry ride each way and a 20-30 min. drive to the populated side of the island- nice day trip)
If you drive the whole way, going through Manteo, check out the Elizabethan Gardens and the outdoor drama about the First Colony. This way is faster and less expensive than the ferry. If you are taking the ferry to Okracoke then to Hatteras, you have to be at the landing at least 30 min early and they direct you into a lane of traffic for loading purposes. It is time consuming and the drive to Cedar Island Landing is one lane each way through very rural, but interesting locals with many marshes and canals. (fill up with gas before leaving the 4 lane!)
Housing is varied with prices just as varied. Anything from a campground with camper and tent sites being the least expensive of course, to hotels/motels (not a ton of these), and most extensively-rental homes. These also range in size and price.
I would recommend using a realty company. Midgett Realty is the one my dad rents through. You can go to their site and put in the size or price range of rental you are searching for and the area you want to be. You can also search by ameneties. My fathers house, for instance, has an elevator and is completely handicap accessable, has a pool, hot tub, pool table, extensive decks, sleeps 15+, has two refridgerators, two dish washers, internet access, etc. and is basically designed to house a large, extensive family for reunions and such and is quite expensive especially during peak season (July 4) (I could never afford to stay there, even off season!)
It is a beautiful place and very relaxing! Waves and undertow strong at times (more often than not)