Lights depends on what your planning on keeping, budget, and the dimensions your working with.
Skimmer depends on what your planning on keeping, budget, and the dimensions your working with.
Sump depends on your budget, and the dimensions that your working with.
Glad I could help. :thumbsup:
Seriously though, there a lot different ways to skin a cat, and even more ways to setup a tank. More info on the space, and the plans for the tank would help narrow down the choices.