another 2 cents to add...
I have a Coleman 15.5' canoe and started with the foam roof system. Using the foam to load the canoe requires two people. I upgraded to a proper roof rack and can load the canoe by myself by sliding it on the rack. For a longer trip with an accomplice I actually prefer the foam since the canoe sits lower on the car and appears more stable.
Depending on your budget you may wish to consider having both.
Our 15.5' is large enough for two adults, all our fishing gear and 2 Golden Retrievers.
Your canoe choice will also require some consideration of the construction/material. Our canoe is indestructible since it is made of RAM-X.
Just about any canoe will suite your needs on the water. The issue is how you get it to/from the water that will help determine what you get.
cheers.