They have better beaches, we have lovely mountains.
Honestly, from an outsider's perspective I can hardly tell the difference culture-wise, and I've been living here five years.
edit: Banks. Banks be the difference.
Outer, or the kind with money?
The thing I always notice is physical. If you're driving down I-85 or I-95, you can literally tell when you've crossed the line by looking at the countryside. The trees suddenly look stunted, the split-rail fencing is replaced with chicken wire, and everything just looks.....poorer.
And I'd say there's a considerable culture difference. SC was the first state to secede, we were one of the last. SC has always been a bulwark of the old conservative South, NC has long been a model of the progressive "New South".
Not that this is universal across either state, mind you...we had lynchings here and re-elected Jesse Helms for decades, and Charleston and Columbia have their pockets of free spirits and liberal thinkers. But in general, I tend to agree with former poet-laureate (and former professor of mine) Fred Chappell when he said that "North Carolina is just north enough that it's not too Southern, and just south enough that it's not too Northern".
Oh, and you can't tell me that Myrtle Beach is anything to envy. Not when we have like three times as much coastline and lovely quiet little coastal towns as opposed to one giant strip of mini-golf, Wings and cheap motels.
EDIT: I feel like I should qualify all of the above by saying that South Carolina has produced a number of awesome people and personal friends. It's just that most of them left the state and moved elsewhere....