Battery question for SF
 

I am rigging my 74 23 CC SF with new electronics and am wondering your thoughts on batteries. I have a Garmin 5212 with fuel flow, GPS, Weather, XM, a VHF radio, CD player and regular gauges for everything else. The boat has always had two deep cycle (house batteries) with a switch and basic electronics and the previous owner said they never had any problems starting an Ocean Pro 200. They also were in NJ and I am in Maine where it can get cold. With all the electronics I am leaning towards keeping 2 house batteries. Should I go one starter, one house? Install 3 batteries??