Sodas were my problem too, I used to drink 4 or 5 a day (or more). I cut them out of my diet and the weight started to come off. If you are going the low-carb route, you will want to keep the juices to a minimum. Water is always good

Just a tip though... Get yourself a good multivitamin while you are on the first couple of phases of the low-carb diet.
I personally am not one to go to the gym. I hate exercising just to exercise. That is why I have picked up Tennis, and bike riding. If you have a bike, start there. Go out for a ride around your area every night either alone or with friends. If you need to pick up one or two things from the store ride your bike there (if its fairly close that is).
Let me tell you a VERY useful secret that not many people know. BE HAPPY! When people are happy, they have more energy, they are healthier, and they have a MUCH better outlook on life. If you cannot keep yourself happy, meet some happy people. The type of people that are fun to be around because they are energetic and easy to get along with, and won't be happy just sitting around watching TV.