I'm sure you already know how many good school districts there are in the Chicago suburbs, so fortunately, there are a lot of great communities that you may love. I'm from Texas originally (no public train system), and so the Metra system is something I believe is fantastic. I commuted on the train downtown from our home in Western Springs for 3 years before our kids were born, and I loved it. It provided natural preparation and decompression time before and after the professional part of my life.
We made proximity to downtown a priority, because Chicago is an amazing city, and we didn't want to miss out on shows, restaurants, the lake and museums. We also wanted to be able to go on vacations without it including a horrible trip to the airport. That's how we ended up here: 5 minutes to the train, 30 minutes to O'Hare, 30 minutes to downtown, 20 minutes to Midway. We've been here 16 years, and absolutely love it. I'm glad we put so much thought into where we would want to be in the long run.
I suggest sitting down with your husband and making a list of your important priorities and lifestyle preferences. Some of those lists of "Best Places to Live" in the magazines may help you think of things you'd otherwise overlook.
Good luck! I hope you find a great place to put down roots for your family!