As far as I know there is no X10 to bye bye standby gateway.
What sort of lighting control do you want. Low level lighting means many things do you mean dimming control, just outside, just inside or just simulation of occupancy or all of it.
X10 is still quite a good system if done properly. Starting small then enlarging the x10 system is the best way to go. It makes it easier to fault find.
Heating- What is it that you actually want to do here, apart from the remote control. Only have it on when there is someone in the house and when the house is empty it will only come on when the temp drops below a set value, so it doesn't get too cold.
The problem is that while some of it can be done cheaply to be able to text and have internet control means spending some more money.