PMoyer...excellent post. I'm sure it will be helpful to some new buyers!
I will take a moment to comment on each of your "rules":
Rule 1: Do Not Hurry. I don't think most people will have your patience or passion for learning...though one can't argue with your premise. I think most folks can make a decision on a first boat within a few months and it will be hard to go too far wrong unless they plan on going blue water cruising. As long as they plan to stay close in shore and get a good survey, almost any boat will be fine. The more prepared you are with understanding your real needs...the BETTER the choice will be but I'd still take a Valiant 42 on the ChesBay rather than wait a year to settle on a Catalina. Worst case...I sell the Valiant and buy the Catalina.
Rule 2: Be Honest With Yourself. Another good one...but one of the recurring themes here is folks wanting to go blue-water and cross oceans when then don't know what that is all about AND don't like it when they try it. There's a reason Georgetown Harbour in the Bahamas is called "Chicken Harbor" and why south Florida has a lot of nicely equipped cruising sailboats for sail...lightly used! People bought these 'cause they honestly believed they would enjoy the cruising life and long distance sailing. Many don't.
Rule 3: Don't worry about the money.
Here I disagree...if the goal is long distance cruising/living aboard. In my experience, most people have to worry about the money and cannot afford the loss that comes with a two or more boat approach to finally getting the "right boat". I agree with the need to really research the right type of boat for the planned cruising agenda and then find a suitable one that is affordable. But if a Tayana37 is the right boat...there is no need to get a Hunter 28 to learn on first in the "Bay" Not doing so will save a LOT of money and buy a lot of rum drinks somewhere nice!!
Rule 4: Read, think, and learn.
Yeah...I agree...but it is interesting that I've never read even ONE of the books on your list....and I've read a lot of sailing stuff over the years. I think that the CG boating course for sailing is very useful for beginners and Calder's stuff on diesels and electrical systems is invaluable but the best advice I can give is just to read a lot about sailors and boats following your own interests. There is so much more available on line today as well that can short cut the learning curve....and not just here. What you don't learn from reading...the boat and the sea will teach you!
Rule 5: Rethink your requirements.
I do think you have to be open to other ideas...but I also think that it is a mistake to make too many sacrifces to things you would like to have in boat. ALSO....make sure "your" requirements include your family's wants and needs. A "Pardey" approach may work for some couples but they are rare. It may be better to change your cruising plans...than give up too much comfort/lifestyle stuff in order to "live your dream". As one woman said to us..."I am letting him live his dream of going cruising...but I did not agree to go camping for 5 years."
Hope this adds a bit to the search process for some of you.