JW, thanks for stepping in there and explaining the drawbacks of 20 amp circuits as general lighting circuits. I just don't explain it the way you do.
Steve, sorry if I sounded snotty, but I did say I was confused, and then you acknowledged that you were joking. I have seen several 1000 sqft bungalows from the '40s have a second story put on them, a standard sized lot around here is 6000sqft and often it makes more sense to go up. But I know that the floor must be torn out and all the foundations reinforced. So if you want to joke about going to a third floor, you will trip me up.
Back to your concerns about load demand. Yes, once upon a time 60 amp services with four fuses were common in the bungalows around here. I have replaced a few of them, but there are not many that were not updated decades ago. And those updates are getting replaced.
But efficiency is king. You were positing the demand of dozens of halogen lights. And now you acknowledge that LEDs are available and obviously are more efficient.
The CURRENT code demands that you provide 3 va per sq ft, which works out to 42.5 amps, in general lighting circuits. You don't get to round down.
So you can install three 20 amp circuits and deliver 60 amps, or three 15 amp circuits and deliver 45 amps, or take my advice, and put in four 15 amp circuits and have 60 amps available, which is about 30% over the minimum requirement. Quicker, cheaper, easier, and as JW illustrated, SAFER.
And shop around for some more efficient TVs please, the ice caps are melting. While you are wiring the room, you can put a switch on the wall that turns off all the power to the entertainment "vampire" load. That stuff is deadly on your electric bill. There is no need to have it on when it is not in use, is there?
You mentioned the idea of a new kitchen addition. When I work up such a project, I assume six circuits or so. Two 20 amp counter circuits. A 20 amp dedicated circuit over the stove for the inevitable microwave range hood (my inspectors really push that one, and I don't currently push back). The garbage disposal and dishwasher get another dedicated 20 amp circuit, and both of them have cords that plug into an outlet, that is the latest code.
The refrigerator I always put on a dedicated circuit when working from scratch, why not? 15 amp is sufficient unless it is big enough to hang sides of beef in.
If the laundry is anywhere near by, it gets a dedicated 20 amp circuit. And the lighting for the kitchen is on none of the circuits described.
On one occasion it made sense for me to just put in a 50 amp subpanel for the whole kitchen, that ended up saving lots of wire. Most of the time, the original plan has the service panel near the kitchen for obvious reasons, so that was the exception. What you describe may be another exception.