Solar vs. Low-Voltage:
Solar landscape lights are the easiest to install because you literally stick them into the ground and they charge themselves with the sun's rays. They typically cost less than traditional low-voltage lighting. The downside to solar lighting is that the light emitted is usually dim, and after a while the battery won't hold a charge anymore.
The alternative to solar lighting is low-voltage landscape lights. It is a misconception that you need to hire an electrician to install low-voltage wired lighting. This is a project that any homeowner can handle, no electrical experience necessary.
Low-voltage lighting consists of three parts: a transformer, low-voltage wire, and the light fixtures. Before making your purchases, plan the layout of your lighting. Avoid runway style lighting along a path (lights symmetrically lined up on either side of the path.) Stagger lighting for more visual interest and natural looking light coverage.
Once you have a plan, add up the total number of light fixtures. Next determine the wattage of the bulb for each fixture. Add up all the watts. Purchase a transformer that can handle more than the total of the wattage needed. Purchase wiring that matches your transformer's specifications. To make your life easier, choose a transformer that has a dusk and dawn (photo cell) sensor.
It is a good idea (but not necessary) to purchase all your parts from the same manufacturer. This should ensure that they will work in conjunction with one another.
Install the transformer on the wall of your home next to a GFCI outlet. Follow the manufacturer's instructions for mounting height and wiring connections.