Chicago. I can get a fairly good variety of beers but never nugget or rajah. I can get great Chicago beers like Three Floyd's, Pipeworks, Half Acre, Two Brothers, Goose Island to name a few.
The only "local only" beer GI makes is Green Line pale ale, but it's only available on tap.
Some other ones that might not be available in your area are their vintage ales:
Pepe Nero
Matilda
Sofie
Pere Jacques
Juliet - Availability for this is hit or miss since it was limited release
Otherwise I'd be interested trading strait up 6er of Zombie for a 6er of White Rajah or Nectar.