Personally, I would start out with a 4 gallon. Most of your boils are going to b 2.5-3 gallons when you start out anyway. It's an inexpensive way to start brewing in case you decide later you don't have the time to do it anymore. You can always go bigger later, and you will find that no matter how much you try to plan in advance, you will likely find your initial brewing equipment isn't your dream equipment at some point down the road. A lot of these guys will tell you to buy as big as you can afford, but I see you are brewing on an electric stove top, and you will be lucky to get more than 4 gallons boiling with that kind of power. Besides, you don't have to throw out your 4 gallon pot just because you get a bigger one. You will be surprised to find how much liquid needs to be heated during the brewing process.