Hi!
I'm not sure if you're looking for advice or just poll votes, but... As a current resident of Minneapolis who didn't apply at the Humphey and who did apply at SPEA, I'll weigh in.
I've been living in Minneapolis for 2 years, and really, really like the city. I think (unless you've visited) that is is probably larger/more urban that you're picturing. 3 million isn't huge, but it isn't peanuts either. The Humphrey's public policy program is a great program, and I totally would have stayed here, but their environmental policy offerings are pretty weak compared to other schools, and enviro policy is what I want to do.
Based on sheer size of the job market, and the fact that the U of Mn isn't the only economic driver in the Twin Cities (as opposed to IU and Bloomington), I think it would probably be easier for you to find a part time job or internship while in school. However, if you are looking for a summer internship where you can travel, my impression is that SPEA has significant networks in Chicago and DC, and that the career services dept. is very helpful with intern placement.
In regards to postgrad opportunities, what I've heard (and this may or may not be 100% accurate), is that the Humphrey's career networks are either regional (read: in Mn) or in DC, and that SPEA's networks are in Chicago and DC. I also get the feeling that SPEA is a little more well known on a national level, but again, I could be wrong...
Good luck making your decision