First, let's put our solar system's size in perspective:
With current tech, it takes 9 months for a one way trip to mars, 21 months (1 year 9 months!) to go and come back due to planet rotations and stuff.
To travel to Titan, the most earth-like moon we could look into terraforming, it would take 7 years for a one way trip, and I don't even know how long to go and come back. Our tiny corner of the universe is already this big.
Currently? We get what we can, so ocean. Later on when we can actually go to new planets? Space, baby.