Are you looking for in-sump or external? If electrical costs are a concern, then you need to go with a needle-wheel skimmer like a Deltec. If you aren't too worried about electrical costs, then go for a Beckett skimmer driven by a good pressure rated pump.
I have about 270g total volume in my system, and I am using a MRC MR3 dual-Beckett driven by a Blueline HD70. It is a great combination that I am very happy with.
It is hard to make a good skimmer recommendation without knowing your system setup, needs, etc. Give us some more information and then you can get a informed recommendation.
Mike