Whatever you buy, remember that you are learning this hobby, and buyingthe most expensive items might be the right move yet. Sooner than later you will, a) determine where the hobby is for you, and b) find you might not want to use some of the products that other people do to sustain your system. When I started out about 2 years ago I bought a used tank, a PC light and a traditional filter and a hang on the back protien skimmer. My total investment on dry goods was right at 200 bucks. I did it that way to make sure I liked what I was doing.
As far as starting you 75 out I would go with a simple 3 chamber sump/ refugium combo, and return in the middle. As a return pump you could go with about 700gph according to Melev's Reef's Mark Levinson. I would get a insump prtien skimmer from Aquarium Designs. They have a PM skimmer for about 100-125 that would work perfect for you.
If you don't have the money for a custom acrylic sump, get a submersible pump and a dinged up old 30 gallon tank off of this forum or Craigslist. Then you can get some glass for baffles.
For lighting, go for what you can afford, but try to go T5ho or Metal Halide
Unless you are buying a highpriced wavemaker, 2 Koralia 3's will do get things moving. Be sure when you are plumbing to use spaflex PVC or flexible hose lines, black or clear from HD/Lowes.
Oh, RO/DI unit is a must unless you like driving to the fish store every 2 days for top off water.
30L w/10gallon sump 4xt5ho; Up and running:125g long, 30g sump, 50g fuge.
"Life is tough, but it's tougher when you're stupid.”
John Wayne