PC lights will be fine, nice lights are good since they really show off the colors of the fish, so PC work pretty nicely.
As for a skimmer, depending on your fish, the bigger the better - puffers, triggers, lions, groupers all produce enourmous bioloads - they produce a ton of waste due to their predatory, high protein diet, and in some case their messy eating habits which leave a lot of missed food behind.
I think fuges can be very nice on fish tanks, but they aren't required. Honestly not a bad idea because they do sponge up spare nutrients that can foul your water and lead to algae growth.
In a 168 you can keep a nice variety of fish - lions, puffers, triggers, tangs, groupers, wrasses, angels are all good candidates.
I would say figure out the fish you want to keep, and plan from there.
Also do you want a few big "showcase" fish like clown trigger or porcupine puffer, or do you want smaller fish like dwarf angels, hawks, etc. You stocking decisions may affect your equipment demands.
