When you are looking into what sort of patio lights to install in your backyard you need to consider the following criteria.
First you need to assess exactly what you will be doing on your patio when the lights are on. For instance will you be sitting around a table and eating? Will you be relaxing with a drink perhaps and enjoying the evening and the lighting effects created by your patio lights? Or will you be working, say in the area around the barbeque.
The answer to these questions results in different types of patio light being used. In the case for instance of lighting the barbeque area you should be thinking of task lighting; lighting bright enough to illuminate the task at which you are working but no so bright as to spill into neighboring areas and spoil the light there.
If you believe your main use will be to sit and enjoy the garden, lighting effects and all then you should concentrate on installing accent lighting. This sort of lighting is used to throw light onto certain objects in a dramatic and pleasing way. For instance you may have a water feature on your patio and it may be a good idea to light that, say from below thus creating lots of light and contrasting shadows. Or you may have an interesting wall which can be thrown into stark relief with the right sort of wall patio lighting. You really can have a lot of fun with accent lights and they can make your overall patio lights really effective.
So in summary, when trying to decide what the best options are for you patio lights it is important to consider the use you intend to put the patio to at night. If you overlook this simple step you may well be disappointed and not get the enjoyment you deserve from your outdoor space at night.