I think if you are waivering that close to getting a #3, you probably should just do it. In the end, when you figure how many years this thing will last the extra dollars will seem like nothing and the extra space that you will have for that rare occasion where you want to cook for a large group you'll be able to do it.
I am a single Dad, with two kids and love that I went with a #3. It is surprising how many opportunities that I get to cook for large groups, be it church potlucks, kids confirmation and graduations, block parties, family camping trips, etc.