Do you need a skimmer: no. Will you likely have more success with your tank with a skimmer: yes!
Skimmers do a lot of really good things for the tank, remove organics, aerate, cool, etc... so life is just better with a skimmer on that sized tank. I normally put it this way, on tanks less than 20g skimmers are not worth it. Tanks 20g-50g, skimmers are functionally optional as water changes can keep up. On a 50+ such as a 110g skimmers save money, time, and livestock lives. While you do not "need" one, it make things easier to the point that having one seems like a necessity.
Oh, my recommendation: Minimum: Octopus NWB150, slightly better: Octopus NWB200, Octopus Extreme 160, Preferred: Super Reef Octopus 2000INT
Now, since you are newer, the biggest "trick" in the hobby is the so-called "ratings" on skimmers. Most are a down right lie, some are severely stretching it, and a very honest few are slightly realistic. So when looking at skimmers, do not look at the rating, look at the pump (the air draw) and the skimmer body size. You want a pump draw at at least 15-20scfh and a minimum body diameter size of 6 inchs.
Last edited by FutureDoc; 02-25-2011 at 01:54 PM..