Which Battery is best?

[SC77MA]

I have a 1977 20'MA, with a 200 HP Mariner. Time to purchase my first set of batteries. I have a perko switch, 2 batteries, 1 deep cycle, 1 starting. Can anyone recommend a starting battery that would be appropriate? A good deep cycle battery? My only electronics at the moment are the standard lighting, an illuminated compass, a GPS and a fish finder. Any recommendations would be greatly appreciated.....