Hey CLT, my DH is from Charlotte and we live in Charleston. I'd be delighted to bore you to death with details of my lovely and wonderful home state!
Beaufort is indeed nice, and has a charming, small town feel to it, but there isn't much in the way of "big city amenities" nearby, not like Charlotte. In fact, I would say that nowhere in SC has those kind of amenities, except Greenville, that you would want to live!
Along the coast, there are many nice small towns, starting up by Myrtle Beach (Conway, Murrels Inlet, Pawleys Island, Georgetown (truly beautiful downtown historic district and nice shops--a real favorite of mine), Mount Pleasant is ridiculously expensive (I work there and we call it Mount Plastic) and the traffic sucks, but the greater Charleston area has lots to offer--low taxes, easy access to the water (and not just the beach, which may or may get old) and access to what passes for culture here--read awesome restaurants and the Spoleto festival!
I grew up on Sullivans Island--let's just say that comedian Bill Murray's wife lives there now--and unless a lottery win figures into your retirement, you'll not want to move into a $2 million fixer-upper out there, likewise Isle of Palms. Shame, really, but you know the steadfast drumbeat of progress.
We lived on Folly Beach for about 10 years, loved it, but it, too has succumbed to McMansion fever, and there are fewer bargains to be had, but the beach is beautiful and the downtown funky and fun, with great restaurants, live music, and a cool pier.
Bluffton is also nice, just outside of Hilton Head, but has lots of retiree settlers coming in, which probably runs the prices up.
If you come down for a visit, PM me and I'll be glad to offer any suggestions for the so-called Lowcountry and maybe get y'all out for a boat ride in Charleston harbor. We live on one of the "sea island" in the unincorporated Charleston county, and it is the best of all worlds--4 nice acres with a tidal creek behind, a dock to the sound shared by four houses on our dirt road, with a 20 minute ride into Charleston proper when we need some dress-up time in the City! Along those lines, look at the tiny towns of McClellanville and Awendaw (both outside Mt. Pee) and Edisto Island further south (more rural but the town of Edisto Beach is very neat, and actually has potentially affordable homes within walking distance of the beach).
Summerville is okay, sprawly and uncontrolled growth without much regard for zoning, but there are nice places among the ticky-tack, and the downtown is really neat, especially during the Azalea Festival each spring.
Again, I can probably bore you to death with details, but let me know if I can help in any way! Southern hospitality and all that!