Electric/Gas - These are pretty much required, especially in MN. You can help by turning off lights, unplugging devises, and keeping the temp in your home at a moderate level. We don't have AC but we keep our house at 68* during the day in the winter and 62* at night. It saves a lot on our bill and we get to wear snugly sweaters. It also helps if you do some winterizing in the fall, but that will be a different post.
Phone - People are addicted to their phones. We made the decision to switch to a land line with the most basic service. We weren't making long distance phone calls anyway, so we just don't have long distance service. We don't need to text, we can call or use a multitude of messaging options online. We also feel that when we are out and about having a family day, we don't want to be reached. Our monthly phone bill is right around $16 now, a huge drop!
Garbage - We kept this while we were still changing diapers. Now, we haul our own. We are spending about $5 a month on our garbage now. It is free to recycle and we get things sorted better now. Plus we bring in cans when we go and it usually covers the cost of the garbage and often leaves us with a little extra. It works well for us and is something we recommend. It also means purchasing items that aren't going to fill our trash, less of an issue now that we make many things from scratch.
Insurance - I cannot even begin to describe the amount we were being ripped off by our insurance company! We saved a huge amount on our car and homeowners insurance by looking into new companies. What really burned my biscuit was the fact that our old insurance company covered 0 of our broken sewage line, but our new company would have covered half and we pay nearly half as much to have them!
Cable - Way to expensive and terrible service! We dropped it and have never been happier. We spend about $8 a month on Netflix and it gives us all the shows and movies we want. If you want current series (as they air) you can try out hulu plus. If you are a huge sports fan, this might not work. It is a fantastic way to cut though.
Car Payment - Make sure you have a car you can afford. Here is the real thing to think about though...how many cars do you need? We have 1. Sometimes we have a difficult time juggling, but we know that we can't afford car payment and insurance times 2. I have known so many couples that had 2 new cars and complained about not having enough money at the end of the month.
Those are the only ones I can think of at the moment. It all comes down to what you really NEED. Many of us think we need things, but look at how many people all over the world are living without them. I would love to know how all of you are cutting down on your bills. Let's all learn from each other!