Schlafly is fun to visit, the tour is great, the restaurant is awesome, and it's easy to kill time in their bar. St. Louis wine country is HORRIBLE, hahaha.... they don't filter their wines and they're all very very sweet, I almost felt like I was drinking ice wines even when I was told this was their dryest. They also don't know much about their wine... but I digress.
Hm... St. Louis has great casinos, Hubert Keller's Burger Bar is soooo good, the French district is pretty cool, the Budweiser tour is interesting, the arch is really quite impressive, the museums and science center are free and pretty great, there's this place called Fast Eddie's that is a crazy experience (food is incredibly cheap and good, beer is cheap and decent, and it's crazy crowded)... there's a lot of good food, including a great BBQ place (forget the name).
It's a pretty spread out city though, you def need a car.