[Hairytank]

My floors and I have personal experience with the Coralife skimmers..they are difficult to get the settings right and they have a habit of overflowing the collection cup. Since you will have a sump you could put one in there thereby preventing any overflow issues, but again you get what you pay for in terms of their ability to skim.

Some poplar ones that can be had between $150-400ish (new and/or used)
Euroreef RS135
ASM (G-1X or G-2)
(There are many forums that discuss the pros and cons of ASM Vs Euroreef skimmers. Just gooogle that, ASM are cheaper and basically the same other than they are a little less sturdy)
Precision Marine RL100 or RL150
Aquamedic Turboflotor 1000- (Good, but very large...)

Canreef usually have a couple of protein skimmers a month come up for sale.

I have used both the Coralife (sitting in my basement where I can curse it every chance I get) and the Aquamedic. I am sure someone will provide info on the other option avaliable.

Spend a little extra the first time or you will wind up paying again and more later when you want get a better one...JMO