If you were going to heat water for hydronic heating you would use and appliance designed for that purpose (boiler) Being that your in SF, I doubt your water temp would need to exceed 160 degrees. Your best bet is to use a modulating condensing boiler that would have efficiencies up to 96% with nat gas.

Which would be more appealing to the general mid-level homebuyer? The OP has probably made her decision, but I'm going to weigh in anyway. The best way to answer this question is to look at other homes in your price range, in your area. Oftentimes the "general mid-level homebuyer" is not overly concerned with anything beyond the appliances being newish and clean, and doesn't expect anything beyond a flat top electric. While I agree that induction is a great alternative, it's still a mystery to most people (Kelly Ripa's Electrolux ads notwithstanding) and buyers may be discouraged by needing to replace some or all of their cookware to use this unfamiliar technology. Gas is a favorite among cooks and foodies, but they are a smaller percentage of "the general mid-level homebuyer" population as a whole. And of course if your home is in an area of luxury homes with expensive kitchens (regardless of whether they're used or not!) you need to take that into consideration. So, look at what your comps offer, do the same, and point out that there are additional hookups.

When you refer to "electric stove", your search words on the internet should be "induction range". The "electric stove" with coils or electric-under-glass that I think you mean is being outmoded by induction. Induction ranges or cooktops are powered by electricity. Will this still make my look that i woukd like to achieve? Since you did not tell us what look you are trying to achieve, it is impossible to answer specifically to your kitchen. However, an induction range should go anywhere. Your words "a nicer hood" could mean anything, so there is no way to advise you on the hood without more information on what you are talking about when you say "a nicer hood".

Cooling and dehumidification are separate, but related functions of an HVAC system. The 2 1/2% summer design conditions for San Francisco (77F d.b. 64F w.b.) have a corresponding relative humidity of 64.3% That's above the minimum required for initiation of mold/mildew growth (and once established mold/mildew can propagate at 50% r.h.) and outside the 35% to 55% range recommended by the NWFA for stable hardwood floors. So, even if 77F is considered a comfortable indoor temperature, the need for control of relative humidity is indicated. Unfortunately, attempting to decrease relative humidity by cooling from 77F to say, 73F will likely result in short cycling of the system, little if any moisture removal, and cool-and-clammy conditions. (My psychrometric table indicates the relative humidity would be 73.4% if the system produces cooling without dehumidification.) The summer design temperatures for San Francisco aren't unique experiences for folks in the Bay area. They are similar to conditions we encounter in our coastal Virginia area for two to three weeks each spring and fall when there is little demand for either cooling or heating. During these "shoulder seasons," controlling relative humidity requires a dehumidifier. I have a dedicated dehumidifier integrated with the HVAC system on each level of my home. They aren't code mandated, and they don't operate often, but they are an investment I chose to make for a healthier indoor environment and more stable hardwood floors and trim.