My friends and I go sit in Grand Park every year. Don't be put off by the huge crowd, it can also be lots of fun as long as you are in the mindset to deal with the crowds. It doesn't get packed shoulder-to-shoulder like I understand it does in Boston (I'm talking about the lawn, not the Taste) and we just get our spot later in the afternoon and pretty much stick to it, maybe venturing to the edges of the Taste. The streets will all be closed off in the Loop proper afterwards, and extra trains and buses will be running. If I drive, I generally park in the West Loop area, it's about a mile walk in and out or I take the bus in and walk out with my friends who live in that area. What I'm saying is, don't worry so much about the perfect spot, just grab a blanket and go. One year we watched from a pedestrian bridge in south Grand Park, and we missed hearing the music (although last year the canned music to the fireworks was truly awful).