Solar powered low voltage lights are great example of an excellent idea that has been poorly executed. At first look they seem like a great idea, simple to install, just stick it in the ground. Unfortunately their light output is horrible. They show up but they don't light anythihg up. The other downside is they tend to disappear easily. It doesn't take much to yank one out of the ground and walk away with it and install it in your own yard.
The other choice is regular low voltage such as the stuff sold at home depot. A better choice, however you are limited to small distances of wire runs. The voltage drops over the length of the wire so you can't expect to just string out the entire complex on one unit even if you buy a big 500 watt unit. You end up having to buy smaller units and keep the runs under 150-200 feet.