Food Tours

We're visiting New York soon, and as part of that trip we're doing a food tour of the Meat Packing district. It got me thinking -- Austin is a great place for food tourism (I take visitors to both Central Market and the downtown Whole Foods), but we don't seem to have a food walking tour. (Ok, ok, so Austin's not the friendliest walking city, but still....)

So if someone was to start a food walking tour of Austin, where would you take it? Here are my thoughts:

Downtown:
Whole Foods
Downtown Farmer's Market?
IronWorks BBQ
Manuel's

I'm thinking there could also be one of the South Congress area, and perhaps of many of the ethnic restaurants in the North Lamar area. Any other ideas?