I'd avoid the south loop - it doesn't really have much of a neighborhood feel. I lived there for 4 years, and while it's got a great location (close to downtown, the lake, and el to take you to MDW/ORD) it frequently felt like high rise filing cabinets for professionals.

Strongly suggest you check out Ukrainian Village and Wicker Park. Andersonville is nice too, but it will take at least an hour to get to ORD if you take the bus to the blue line.

If/when I move back to Chicago, I'll probably wind up in Ukrainian Village or Wicker Park. Though, being near the lake is really a BIG part of wanting to live in Chicago, and those neighborhoods aren't really near it.