I am a Houston native, but I lived in Destin for about three years. I also visit there about once a year. I graduated from Ft. Walton Beach, (six miles from Destin) high school.
Destin has white beautiful sand and clear blue/green water.
I recommend that you eat at the Back Porch. I waited tables there for a little while and the food is decently priced and tasty. The view is even better. It is situated on the beach and they usually have the windows open.
Another tip. You are only about a 30 minute drive from Watercolor and Seaside. Go to Seaside and rent bikes. It is about 20 bucks for four hours and you can bicycle all along the streets and in the back of Watercolor where there are trails.
We have stayed at the Best Western in Destin twice. It is clean, inexpensive and in a good location across the street from the beach.
Go to the Donut Hole for breakfast, and I recommend Harbor Docks for lunch. Harbor Docks is on the bay and has a great view. Both restaurants have decent prices, Donut Hole is inexpensive.
I recommend AJ's for drinks and don't forget to walk along the docks.
Also, go to Baytowne Warfe and take the courtesy boat over. They have neat little shops and restaurants. Fun for the kids if it is during the day. Not so much at night.
Silver Sands outlet mall does have decent prices and I do recommend parasailing.