Here is one of my old sumpless systems, I had 3 maxijet 1200s, a bak pak skimmer (could of gone without because it wasn't very effective), a heater and 4 overdriven (icecap ballast) 40w fluorescents (probably about 250/300watts of light)
left side
right side
It was a hagen 48g with a couple of fish (the most I ever had was 4 small fish). I wouldn't bother with any kind of filters other then a skimmer unless your just using them to run carbon.
and no, a skimmer isn't necessary as long as you keep up with water changes and stock very slowly