There seem to be some unstated assumptions about athleticism and general balance here, and also, perhaps more importantly, stage in the sport...
It is fair to say that I might grow out of my 12' x 32" aircraft carrier in a few months, but in the meantime, I find it challenging enough heading down the coast side on to a 10 knot chop overlaid on swell.
And there is no way my wife would be having fun on anything less than 11'6". She is not the athletic type and has poor balance. But with the aircraft carrier, she's out there loving it.
So... if I could only pick one for the family to all enjoy right now - it'd be reasonably long and reasonably wide.
That said, I expect soon we will have multiple boards in the family (maybe 10' 6" wide?)