As it was said above, lots of good cables are expensive and needed. They get a lot of wear and tear, the last thing you need is a bad cable and no replacements.
Consider a tech too, if you can hire one, they are expensive, but they save you money in the long run with a smooth running studio. If you can't hire one, find a good freelance tech, be sure to get to know who you want to use before opening your doors for business, you will eventually need them, most likely in the middle of the night -
Dare I say, when things are running smoothly, get an intern, they can help in many ways if you screen them properly...
Oh, and no windows - float the room and have a faraday cage!
Enjoy yourself too!
