I purchased my tank, stand, powerheads, and light first. Set it up and began to read...big mistake. I had to return the stand and build one from scratch to accomodate the height of the skimmer I bought after researching. Wish I bought a larger tank and one that was predrilled. Although I like my light (Coralife PC) I wish I had invested a little more and got the halides.
Really, I should have bought a 20g first and set up the QT. I didn't get into that til about 8 months down the road when I realized how important it was.
This hobby is so addicting it's hard NOT to buy something before you read, read and read some more about it. Lesson learned!