budgets, categories, checking and credit card accounts--how do I make them work together?

I'll give this a try. I haven't yet worked with budgets, so I may be off the mark here.

It sounds like you have several credit cards, and would like AmEx transactions to be included in the "larger" entity Credit Cards. Each card needs an Account so you'll have a register, can download transactions, etc. for it.

To do that, I think you'll want to change the Credit Cards category into an Account and create a sub-account for each card:

1. To delete the CC Category:

Open MD, click on Tools and select Edit Categories. When the Edit Categories window opens, find "Credit Cards", click Delete and Done. (This will undoubedly mean you'll need to recreate your budget; sorry, I know of no ther way to get what you want.)

2. To create the new CC Account:

Click Tools and select Edit Accounts. Click New to get the Create Account window. Click Credit Card and Next to get the Create Account: Credit Card window. Enter Credit Cards in the Account Name field and leave the other fields blank (since this will not be an actual CC account). Set the Currency Type and make sure the Default Category is what I call the Blank Category; if it's not, click on the double arrows just after the Default Category label and scroll to the top of the resulting list. It's a single dot with no label. The verify that the PArent Account is set to Root Account; if it's not, click on the double arrows after the Parent Account label, then scroll to and select Root Account.
Add any comment you like... perhaps something about this being a dummy account to aggregate all your CC accounts.... then click OK.

3. To add individual credit card accounts:

Click on Tools and select Edit Accounts. When the Edit Account window opens, find and select Credit Cards, then click New. Click Credit Cards on the New Account window, and click Next. This will bring you to the Create Account: Credit Card screen. Enter AmEx or whatever credit card name you like in the Account Name field, and fill in the other fields. Then make sure Credit Cards shows in the Parent Account filed. (If it doesn't, click on the up and down arrows and select it.) Add any comment you might like and click OK. Close the Edit Accounts window. Repeat for other cards as needed.

I hope that helps!

Dick