ST. Louis for 2 nights
I haven't eaten many places in downtown St. Louis, so I don't have a lot of means of comparison, and I'm not entirely sure what you're looking for in terms of price, setting, etc., but I had a great meal at the Dubliner (http://www.dublinerstl.com/) a few months ago. It's on Washington.
Tony's is the preeminent St. Louis formal-service, high-priced restaurant experience for decades, now located caddy-corner to the ballpark on the bottom of an office building. They share a kitchen with Anthony's Bar, a more casual offshoot with excellent food and service. Won't go wrong either place, if that is the traditional experience you want. Another contender is Kemoll's, an Italian classic just recently relocated to a new home atop a lofty downtown office skyscraper with what should be amazing views -- I'm awaiting first reports.
If more avant-garde food is your goal, the best place in town is Niche, in Benton Park on the southern edge of downtown just past Soulard. Excellent fare, a nice cross between metropolitan tasting menu innovation and St. Louis big-portion simple hospitality. Another option nearby is Sidney Street Bar & Grill. To the north of downtown is the regentrified Washington Blvd. with the Lucas Park Bar & Grill in a wonderful converted bank building, An American Place in the bottom of the Renaissance Hotel, and a bunch of other places up and down the street. As you head out west you hit the Central West End, with old and renewed places, and then Forest Park, Washington University, and Clayton, where the biggest concentration of restaurants and customers work and live.
To suggest there is "nothing decent downtown" is ridiculous. As noted below, Tony's and Anthony's are both excellent. You didn't specify which meals you are seeking. Roosters makes a great breakfast--try the crepes. Schlafly Tap Room, while not a fine dining location, serves great locally brewed beer and good quality food. An American Place has lost its chef but is a spectular room to eat a meal in. It's definitely worth venturing south just a bit to Benton Park or Soulard for Niche, which features an acclaimed chef, or Franco, or Sidney Street, with the latter serving a non-adventurous but very solid menu. I've never had a bad meal there. You might want to check saucecafe.com for more information about these and other downtown, or near downtown, dining. Don't rely on Sauce for reviews, however. You might also do a search on this board for earlier discussions of the downtown scene.
Larry's Forgione's an American Place
822 Washington Avenue, St. Louis, MO 63101
1831 Sidney Street, St. Louis, MO 63104
1104 Locust St, St Louis, MO 63101
Sidney Street Cafe
2000 Sidney St, Saint Louis, MO 63104
Schlafly Tap Room
2100 Locust St, Saint Louis, MO 63103
10 S Broadway # 150 St, Louis, MO
Franco Bistro & Wine Bar
1535 South Eighth, St Louis, MO 63104
410 Market St, Saint Louis, MO 63102