Hey Tex,
I've lived here all my life and unfortunately have never come across a great anime store in the city.

Mitsuwa is fun but probably not worth the cab ride. You're probably better off just enjoying the sights. For the best view of the city, the women's bathroom on the 96th floor of the John Hancock building can't be beat. And it's also a great place to relax and get a drink (the 96th, not the women's bathroom).
If I wasn't so bogged down with 2 practical exams, 1 written exam, a project and a paper due next week, I would love to meet you.

But please let me know if I can answer any other Chicago questions.
Have a great mini vacation!!

Life is too important to be taken seriously.
~Oscar Wilde