The top beaches in NC for activities you mentioned:
Northern Outer Banks (Nags Head, Kitty Hawk, etc)
Wilmington area beaches (Wrightsville Beach, Carolina Beach, Kure Beach)
Crystal Coast (Emerald Isle, Atlantic Beach and Swansboro)
Brunswick Beaches (Holden Beach, Oak Island, Ocean Isle Beach, etc)
The first three areas have a lot built into them already... the last (Brunswick) is only 30 minutes from Myrtle Beach, which has everything and more (including traffic -- which is an utter nightmare in the summer). The best thing about the Brunswick Beaches is you can enjoy peaceful time with the family, and still make quick escapes for shopping and other amusements during the day to Myrtle Beach.
Check out NCBeaches.com or VisitNC.com for more information.