You said different but you didn't say how. You're in North Carolina, which is one of the places that comes to mind when I think of single-day flights but different than Caribbean diving.
I guess different in that when we went to Grand Cayman after the first dive our first thought was “wow, that looked a lot like Molasses Reef”. LOL. I guess I’m some aspect the Caribbean is the Caribbean.
These are the main options I think of:
1.) North Carolina's offshore wrecks - you're already there and probably did that? If not, don't miss your local diving!
Funny, we haven’t done the NC coast but keep talking about it. When is the best time? I’m concerned about getting seasick on the way. I’ve heard some horror stories.
2.) Jupiter, Florida - goliath grouper aggregation in Fall or the lemon sharks in winter. If you're not opposed to shark feed diving, other times with other shark species like tiger sharks or hammerheads become options.
Edited for Jupiter, we’ve done it a few times and I forgot. We’ve done the Goliath and Lemon Sharks. Saw a few Bulls on the Lemon Shark migration which was cool.
3.) California - granted I did a live-aboard and you guys sound like land resort folks, so I'm not sure where you'd stay, and cold water requires bundling up in neoprene (or dry suits), but how badly do you want to see seals, sea lions and kelp?
Never thought about California. We’re open to liveaboards. Just concerned about which one. We were thinking of saving that for a really awesome trip, like the Maldives.
4.) If you were willing to part with the 'resort' angle, then a trip to dive Cabo Pulmo, or a live-aboard to the Socorros, would give you some serious variety. How do mantas, dolphins and maybe whale sharks grab you?