Bulldog brings up an excellent question but I just wanted to add a general rule and ask a few more questions.
HOB=hang on back btw.
The size of your protein skimmer depends a lot on your bioload, feeding schedule, and tank size. A lot of times you will see a rating for a skimmer ie up to 50/100/75 gallons. Generally, these numbers are way too high (imo). It makes complete sense if you think about it. If you have a 30 gallon aquarium and find two different skimmers: one is rated for 30 gallons and the other is rated for 60 chances are the 30 gallon skimmer is going to cost a lot less. It only makes sense that you should buy it since it conforms to your wallet and your tank size...right? Well, not entirely. You see, a rule of thumb (and I hate rules of thumb) is that you should go with a skimmer that is rated for at least twice your tank size. Remember that this rule isn't always golden. Sometimes a skimmer that is rated twice your tank size is still inadequate and sometimes a skimmer that is rated for twice your tank size, while not inadequate, is simply a waste of money.
So what is your bioload like/what is your stocklist going to be like?
There are a few brands that you almost can't go wrong with, Euroreef and Reef Octopus to name a couple. With that said, everyone will have a different opinion on this matter.
Lovetofly31: I used to have a coralife 65. It worked...somewhat. That's about the only good thing I have to say about it. There are certainly much better skimmers out there.