First of all I hope you had a great trip, and you are right, these boards are a treasure trove of information (and addicting).
While I can't answer the question if
DVC is right for you, there are some questions that you can ask yourself:
1. How often do we plan to go to Disney (WDW or DL)?
DVC points do "expire" after a period of time, depending on how you manage your points and how many points you purchase. In other words, they aren't good forever, and you want to make sure that you are using them as much as possible. That being said, many of us find that once you are in, too many points is usually not the problem!
2. Is this something that financially we can afford?
Don't just think about the purchase costs. There is also interest (if you finance) and membership fees that have to be paid every year.
3. The number of points to buy.
Currently the minimum buy-in from Disney direct is 160 points. Depending on the type of accomodations you would be reserving for your family, and which resort you would most likely choose as your home resort (suggestion would be to choose the one where you would like to stay most of the time to take advantage of the 11 month booking window) - 160 may be too much or too little for you. If 160 is too much, then resale contracts are definitely the way to go to get smaller amounts of points. You will get full DVC membership, even with these small contracts, and you can always add on later.
4. What times of year do you plan to vacation?
A couple of months ago, I wouldn't have thrown this in, but given some of the changes that appear to be coming down the pipe with banking points, the use year (the month when your points for the year start their clock ticking - for instance, I have a March UY, which means that my points for 2007 started on March 1, and will expire on Feb. 28, 2008 unless I use them or bank them). You might want to check out this thread about the new banking rules:
http://www.disboards.com/showthread.php?t=1561084 Don't let the title of the thread scare you - it has some good information to consider.
DVC resorts are more "deluxe" than some of the resorts on WDW property. If your family is used to and happy with staying at the Value or Moderate resorts, you might end up being ahead financially staying at these resorts instead of DVC. However, having a kitchen and a washer/dryer can be nice to have on property (pack less). Remember, too, that DVC resorts do not operate like traditional hotels in that you do not automatically get mousekeeping in your room daily unless you pay extra for it. It's more like a condo, I guess, in that you are expected to be a little more self-sufficient.
Is there some flowchart somewhere to help determine if DVC makes sense for our family?
I don't have a flowchart, but I do have a spreadsheet (actually a "book" of them) that we created to compare the finances during our decision making process. It allows you to compare the costs with different contracts, resorts, etc. We also put in a feature to allow you to compare to the cost of staying at other WDW resorts, and included a "total cost per point" feature that calculates how much each point you use actually costs - including any financing interest, MF's over the life, etc. PM me if you would like me to send it and I would be glad to.
Best of luck - keep asking questions!!