I think Destin will be just what you're looking for.

Destin has a very good nightlife almost year 'round, but it's great during Spring Break. You won't have any trouble finding places to party.

There are more families in Destin during Spring Break than PCB (which is about 90% students during March), so you can't get as loud or rowdy in every place... just a few.

Check out The Swamp and Club Overload.. they've got some great Spring Break concerts in March. Nighttown is usually happening during Spring Break and AJ's is always a good time.

I'll see if we can get Randy from Club Hour in here with more suggestions.