Beer: The new Flying Saucer that's opening at 900 Spruce is going to be my favorite, assuming it opens up by this weekend, and I think it will be. The one in Kansas City is awesome. They have a ridiculous amount of taps and the food is edible, too.
I also enjoy the ample beer selections of these establishments:
International Tap House, Soulard
The Bridge Tap House downtown
Hair of the Dog, downtown
4 Hands Brewery, downtown
Urban Chestnut Brewery, a cheap cab ride west of downtown near SLU
Dive subdivision: Missouri Bar and Grill, Tucker and Lucas
Meshon's/The Bismark (not positive this place is still in business)
Food:
Pi Pizzeria (new one opened up downtown since last Arch Madness)
Schnucks (for breakfast)
Bailey's Range