Converting to gas, considering DHW options

The gas company has run a line to my house and at the end of the heating season I am planning to replace my oil boiler with a condensing gas boiler. I've been considering my options with regards to domestic hot water and was hoping I may be able to get some info here. Here is the situation.

The way the house is currently set up, the oil boiler has a domestic coil which sends preheated water to an electric water heater. The electric water heater is only about a year old, so I probably am not going to replace it right now (though am willing to hear out ideas if someone thinks I should), so the way I see it I have three options.

1- Get a tankless coil in the boiler and use it to preheat the existing electric water heater.
2- Don't get a tankless coil and plan to replace the electric water heater when it reaches end-of-life with a standalone gas water heater (so would need to make sure there was a extra port for gas for the water heater for the future).
3- Don't get a tankless coil and plan to replace the electric water heater when it reaches end-of-life with an indirect storage tank (so would need to make sure the new system is designed to allow an additional zone in the future).

Does anybody have an opinion about what the best option would be?