Well -- I fought the urge to post this -- but lost!!
Secondcurve, I also think a 2HP will be fine if all you want to do is "putt" around. I too live on a smaller pond- when not at Winni-- about the same size (160 acres) and we have some (relatively) reasonable sized boats that water ski/tube etc here. They range from 12ft- 20ft Malibu ski boats.
My thinking is that if you should desire to do anything other than "putt" consider something a little greater in HP. When my son was younger we had a 10ft skiff with an 8HP.
I'm not advocating an 8HP but perhaps you may want to "bump up" your 2 HP and consider something in between. The cost differences are relatively minor.