+1 Blues City Deli in Benton Park- By far the best sandwich shop in St Louis. Great music & atmosphere. Vinny, the owner is one of the friendliest people I have ever met.
Runners up:
Cuban sandwich- La Tropicana in South Hampton
BBQ Sandwich- Pappy's in Midtown
Italian Sandwich- Amigetti's in the Hill
Deli Sandwich- La Grand's Market in St. Louis Hills
ok...I am getting ready to rock everyone's world with this. Blues City Deli in Soulard. The place is nuts. They have limited hours, but people drive for 30 minutes just to go there. The line is usually out the door, but it moves fast. You need to try this place once and then you will be hooked. After you try it I will gladly accept your thanks for gving you the knowledge, but cash works great too.
The BCD is actually in Benton Park. I have eaten at a lot of sandwich places in the 'lou and without a doubt this is the best. Start out with the Benton Park Po-Boy on your first visit and then expand to the Delta Bayou, Redbird, Black and Blue, and so on. Vince and the crew are great and I can honestly say that I get a smile on my face each time I walk in the door. The chip selection is great and the ice for the fountain soda is choice.