Mountains. The beach is great for a visit, but it just doesn't beat the diversity and beauty of the mountains. Sand and waves stay pretty much the same... And what all can you do- swim and sort of half-ass surf. Mountains have camping, fishing (okay, so does the beach!), hiking, mountain biking, backpacking, kayaking, rock climbing, rafting, etc....
This year I think most people in the mountains would most definitely pick the beach right now. Snow is beautiful and we have SO much. I'm all for the beach right now.
That's what I'm thinking! I grew up in Asheville, and while visiting family for Christmas, and am still snowed in. I usually like coming back up from Atlanta to visit. There's something nice about driving through curvy roads and making my way through the Blue Ridge PKWY. I'm normally not much of a beach person, but I do find that the Outer Banks, Charleston, or Savannah are some coastal areas with more charm.
Don't think it's a one-or-the-other thing. Nice thing about the Carolinas is you have both in easy reach. I'm partial to the mountains, especially up around Linville gorge, and down into Lake James. I ride my mtn bike up there, and around Jonas Ridge, Wilson Creek, Table Rock, Pisgah, etc.
And when I go to the beach, it's usually down around Charleston (sorry Wilmington!). Outer banks are just too far (7 hrs from Charlotte), and you just gotta love that Charleston low country for it's history and dining!