I think it would be a huge culture shock for you to be anywhere in NC except the Triangle or Charlotte areas. Pinehurst is very nice for golfers, but there's not a lot of other industry and it's a really small population with the whole of Moore County (including Pinehurst and Southern Pines) having a population of 88,569.
Check out Apex, Cary or Holly Springs if you don't mind being a little bit farther from your friend in Rockingham. Otherwise you might consider some of the outlying areas around Charlotte like Matthews which would be about an hour from Rockingham. There are plenty of affluent areas around the Triangle and Charlotte.
(BTW, I have to quibble with Wikipedia on the counties in the Sandhills. Pittsboro is definitely not in the Sandhills — it's in the Piedmont — and I can't think of an area of Chatham that is in the Sandhills, although perhaps in the very southern part of the county? I grew up in the Sandhills, btw, and live in Chapel Hill now. I could see Lee County and Sanford being in the Sandhills, but I'm pretty familiar with Chatham at least as far SW as Bonlee and I wouldn't characterize it as Sandhills. Here's a map that agrees with me! http://www.unc.edu/courses/2008ss2/g...Regions_NC.gif