I just saw this thread, and I thought back, way back....
Back to when I first got into this industry working for someone else, saw the strengths and weaknesses of the company, went through the highs and lows, built my skills, learned all that I could, then that company folded and went to work for a new start up, where I had direct input into what equipment was purchased ( repeat)
I finally started my own business in 2001, we opened our doors on september 1, by all account through all the research and consultation we did, we had a stellar business plan, and we planned for every eventuality.
......evidently not, 9/11 happened and the economy tanked everyone stopped buying everything. The best laid plans of mice and men. We managed to hang on for about 5 years, but it was a constant struggle.
I can tell you this, take the most frightening situation you've been in ( your first marriage, the birth of your first child, the worst car wreck you've been in, etc) combine them, and then multiply them by 1000000000000000000, and THAT should be the trepidation you should feel, when you contemplate something of this magnitude. More sign shops close every year, then are opened, I'm not sure how this happens, but it does.
I came from the print end of the industry, so we always operated printers first, and subbed cut vinyl out, the operating costs were higher, but the resale prices were comparatively higher as well (exponentially in all actuality)
Think it through, plan as well as you can, but rely only on yourself, not your friends, not your family, not your employees. The only person with a vested interest in your business, is you.
As stated above, if you can read all of this, and not be dissuaded from your course of action, then all the more power to you. The best equipment is that equipment who's capabilities most closely align with your business plan and projected clientèle. You're not talking an insignificant investment so RESEARCH RESEARCH RESEARCH!