You need two electrical outlets (AT LEAST) on the house to be legal. These need to be fitted with "in-use" style covers.

The important thing for planning later landscape lighting is to make sure that you have receptacles placed so that places that are difficult to run wiring to (like under driveways) are reachable.

I second ronnatile's point about accessibility. It's cheap and easy to put in capped lengths of PVC conduit under driveways and sidewalks during construction so you can pull wires easily in the future to all areas. Just mark the locations of the ends of the conduit on a blueprint by taking measurements off things that won't change, like the corner of the house. Measurements from any two fixed points to a particular other point will allow you to triangulate precisely and find the conduit easily in the future when your memory has faded a bit.