Charleston is awesome!! I wouldn't worry TOO much about hurricanes - every one that looks like it's going to hit us ends up hitting Wilmington, NC - so don't move there!! Charleston, though, has almost no job market, is expensive to live there, and the traffic in the suburbs is atrocious!! CofC is a great school, as well as the Citadel and Trident Tech. But public schools are terrible - I could run the Chas County school board better than the people on it now.
A lot of kids go to private high schools. But the city itself is gorgeous, a great vacation spot. GREAT night life, cool historical things to do, great shopping.
I grew up in Columbia. The Midlands are a rapidly growing area. The public schools are actually really good in some parts of town. Football season is definitely fun!! (Go Cocks!) The weather is nice, but if you're from Michigan, you and your family will be miserable your first summer there. It'll take your body some time to get used to the heat. But, hey, that's what a/c is for. Downtown Columbia is alright. I wouldn't exactly say it's a big party or even very pretty, but it's easy to navigate (unlike downtown Charleston where the streets are dangerously narrow). There is a lot to do culturally in Columbia, and it's a nice place to raise a family. As far as hurricanes, they can and DO come to Columbia - Tropical Storm Chris in the mid-1980s and Hurricane Hugo in 1989. The only difference is that maybe some trees will fall down in your yard, as opposed to being on the coast and loosing your whole house! As far as fishing goes, Lake Murray is one of the nation's premiere bass lakes. Lake Marion is pretty good (it's halfway between Columbia and the coast) and there are several good lakes in the Upstate (I date a guy who's into fishing, can you tell?).
I agree with staying the hell away from the Grand Strand. Once you're out of the Myrtle Beach area, you are in the boon docks. The locals are - well, scary. And during the summer, it's so overrun by tourists that you'll want to go on vacation, too - to somewhere far away from Myrtle Beach!!
The Upstate is another place with good public schools, and it is expanding in many industries. Business prospects and job markest are good all along the I-85 corridor between Charlotte and Atlanta.
Happy hunting! SC is an awesome place to live!! Let us know what your family decides.