Radiant floor heating is the most expensive. It is is a lot of extra money to pay for the luxury of keeping bare feet comfortable while walking on the basement floor. You have to decide how much this additional comfort is worth to you. My concrete slab basement in NJ has covered with padding and carpet. If feels comfortable to me even if I walk on it bare foot.

A hot water baseboard system is very nice, but a well designed variable speed forced hot air system can be just as comfortable. You need duct work for AC so adding the furnace is an incremental cost. I would recommend separate HVAC systems for the first and second floors. The basement could be zoned off the first floor system. I would want all the HVAC equipment in the basement and nothing in the attic.

If you do go for a boiler I think the hot water tank should be separate. I think separate and simple is the way to go, but that's just my opinion.

I agree with Mike. Be sure you verify airtightness with blower door testing to get the most out of your insulation. Variable speed or mini splits should meet the loads if the design is efficient. With an efficient home, thermostat response delay of radiant hurts the comfort argument.

If you have a basement or other proper location, steibel eltrons heat pump water heater is a great choice.

I would check out a complete geothermal heat pump system, either liquid to water (all hydronic) or triple function (hydronic heating, DHW & forced air heating and cooling).

http://www.waterfurnace.com/products.aspx?prd=Synergy3D

Then decide for yourself.

IMPO

SR